diff --git a/.env.example b/.env.example
index c926e43..8b528bd 100644
--- a/.env.example
+++ b/.env.example
@@ -57,6 +57,7 @@ SMTP_FROM="noreply@openframe.dev"
 # ============================================================================
 # APPLICATION
 # ============================================================================
+NEXT_PUBLIC_APP_URL="http://localhost:3000"
 # development | production | test
 NODE_ENV="development"
 # Disable all app-level rate limiting for local testing. Leave unset to keep rate limiting enabled.
@@ -86,3 +87,11 @@ NEXT_PUBLIC_BUNNY_CDN_URL="your-url-to-bunny-cdn"
 # Bunny orphan cleanup configuration (script + external cron; app runtime does not schedule this)
 # Grace period is fixed at 24 hours in the script.
 # */15 * * * * cd /home/yusuf/Programming/OpenFrame && bun run bunny:cleanup-orphans
+
+# ============================================================================
+# BILLING
+# ============================================================================
+# Stripe recurring price used for paid accounts
+STRIPE_SECRET_KEY="sk_test_..."
+STRIPE_PRICE_ID="prod_UBWFFKZC3d80z4"
+STRIPE_WEBHOOK_SECRET="whsec_..."
diff --git a/app/(dashboard)/dashboard/page.tsx b/app/(dashboard)/dashboard/page.tsx
index df2476b..76adeee 100644
--- a/app/(dashboard)/dashboard/page.tsx
+++ b/app/(dashboard)/dashboard/page.tsx
@@ -2,7 +2,9 @@ import { auth } from '@/lib/auth';
 import { redirect } from 'next/navigation';
 import { db } from '@/lib/db';
 import { Prisma } from '@prisma/client';
+import { hasCollaboratorBillingBackedAccess, requireBillingAccessOrRedirect } from '@/lib/route-access';
 import { DashboardClient } from './dashboard-client';
+import { buildBillingAccessWhereInput } from '@/lib/billing';
 
 export default async function DashboardPage({
     searchParams,
@@ -14,6 +16,11 @@ export default async function DashboardPage({
         redirect('/login');
     }
 
+    const hasCollaboratorAccess = await hasCollaboratorBillingBackedAccess(session.user.id);
+    if (!hasCollaboratorAccess) {
+        await requireBillingAccessOrRedirect({ userId: session.user.id });
+    }
+
     const userOnboarding = await db.user.findUnique({
         where: { id: session.user.id },
         select: { onboardingCompletedAt: true },
@@ -37,6 +44,7 @@ export default async function DashboardPage({
             { members: { some: { userId: session.user.id } } },
             {
                 workspace: {
+                    owner: buildBillingAccessWhereInput(),
                     OR: [
                         { ownerId: session.user.id },
                         { members: { some: { userId: session.user.id } } },
@@ -44,6 +52,9 @@ export default async function DashboardPage({
                 },
             },
         ],
+        workspace: {
+            owner: buildBillingAccessWhereInput(),
+        },
     };
 
     // Build unique workspace list for filter (Needs an unbounded list of accessible workspaces)
diff --git a/app/(dashboard)/layout.tsx b/app/(dashboard)/layout.tsx
index dfc19e9..fcf000c 100644
--- a/app/(dashboard)/layout.tsx
+++ b/app/(dashboard)/layout.tsx
@@ -1,5 +1,6 @@
 import { Header } from '@/components/layout';
 import { auth } from '@/lib/auth';
+import { hasAppNavigationAccess } from '@/lib/route-access';
 
 export default async function DashboardLayout({
   children,
@@ -7,10 +8,13 @@ export default async function DashboardLayout({
   children: React.ReactNode;
 }) {
   const session = await auth();
+  const showAppNavigation = session?.user?.id
+    ? await hasAppNavigationAccess(session.user.id)
+    : false;
 
   return (
     <div className="relative flex min-h-screen flex-col">
-      <Header user={session?.user ?? null} />
+      <Header user={session?.user ?? null} showAppNavigation={showAppNavigation} />
       <main className="flex-1">{children}</main>
     </div>
   );
diff --git a/app/(dashboard)/projects/[projectId]/page.tsx b/app/(dashboard)/projects/[projectId]/page.tsx
index ffd0c93..f359c55 100644
--- a/app/(dashboard)/projects/[projectId]/page.tsx
+++ b/app/(dashboard)/projects/[projectId]/page.tsx
@@ -4,7 +4,7 @@ import {
   ArrowLeft,
 } from 'lucide-react';
 import { GuestGate } from '@/components/guest-gate';
-import { auth } from '@/lib/auth';
+import { auth, checkProjectAccess } from '@/lib/auth';
 import { db } from '@/lib/db';
 import { ProjectContentClient } from './project-content-client';
 
@@ -65,6 +65,8 @@ export default async function ProjectPage({ params, searchParams }: ProjectPageP
     notFound();
   }
 
+  const access = await checkProjectAccess(project, session?.user?.id);
+
   // Check access
   const isOwner = session?.user?.id === project.ownerId;
   const isMember = project.members.length > 0;
@@ -92,7 +94,7 @@ export default async function ProjectPage({ params, searchParams }: ProjectPageP
     }
   }
 
-  if (!isOwner && !isMember && !isPublic && !isWorkspaceMember) {
+  if (!access.hasAccess || (!isOwner && !isMember && !isPublic && !isWorkspaceMember)) {
     if (!session?.user?.id) {
       redirect('/login');
     }
@@ -139,7 +141,7 @@ export default async function ProjectPage({ params, searchParams }: ProjectPageP
     };
   });
 
-  const canEdit = isOwner || project.members[0]?.role === 'ADMIN' || workspaceRole === 'OWNER' || workspaceRole === 'ADMIN';
+  const canEdit = access.canEdit && (isOwner || project.members[0]?.role === 'ADMIN' || workspaceRole === 'OWNER' || workspaceRole === 'ADMIN');
   const isAuthenticated = !!session?.user?.id;
 
   const projectData = {
diff --git a/app/(dashboard)/settings/page.tsx b/app/(dashboard)/settings/page.tsx
index ed66eb0..e9d93d3 100644
--- a/app/(dashboard)/settings/page.tsx
+++ b/app/(dashboard)/settings/page.tsx
@@ -1,7 +1,21 @@
-import { requireAuthOrRedirect } from '@/lib/route-access';
+import { hasCollaboratorBillingBackedAccess, requireAuthOrRedirect } from '@/lib/route-access';
+import { getBillingOverview } from '@/lib/billing';
 import SettingsPageClient from './settings-page-client';
 
 export default async function SettingsPage() {
-  await requireAuthOrRedirect();
-  return <SettingsPageClient />;
+  const session = await requireAuthOrRedirect();
+  if (!session?.user?.id) {
+    return null;
+  }
+
+  const [billing, hasCollaboratorAccess] = await Promise.all([
+    getBillingOverview(session.user.id),
+    hasCollaboratorBillingBackedAccess(session.user.id),
+  ]);
+
+  return (
+    <SettingsPageClient
+      billingOnly={!billing.subscription.hasBillingAccess && !hasCollaboratorAccess}
+    />
+  );
 }
diff --git a/app/(dashboard)/settings/settings-page-client.tsx b/app/(dashboard)/settings/settings-page-client.tsx
index 6c64c76..5c6e64b 100644
--- a/app/(dashboard)/settings/settings-page-client.tsx
+++ b/app/(dashboard)/settings/settings-page-client.tsx
@@ -1,7 +1,7 @@
 'use client';
 
 import { useState, useEffect, useCallback } from 'react';
-import { Bell, Send, Mail, CheckCircle2, AlertCircle, Loader2, Globe } from 'lucide-react';
+import { Bell, Send, Mail, CheckCircle2, AlertCircle, Loader2, Globe, CreditCard } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
@@ -32,6 +32,32 @@ interface NotificationSettings {
   timezone: string;
 }
 
+interface BillingOverview {
+  isConfigured: boolean;
+  checkoutAvailable: boolean;
+  portalAvailable: boolean;
+  subscription: {
+    status: string;
+    label: string;
+    hasActiveSubscription: boolean;
+    hasActiveTrial: boolean;
+    hasBillingAccess: boolean;
+    priceId: string | null;
+    currentPeriodEnd: string | null;
+    cancelAtPeriodEnd: boolean;
+    cancelAt: string | null;
+    trialEndsAt: string | null;
+    billingAccessEndedAt: string | null;
+    storageCleanupEligibleAt: string | null;
+  };
+  workspaceCreation: {
+    canCreateWorkspace: boolean;
+    reason: string | null;
+    ownedWorkspaceCount: number;
+    invitedWorkspaceCount: number;
+  };
+}
+
 function ToggleButton({
   enabled,
   onToggle,
@@ -77,7 +103,7 @@ function ToggleButton({
   );
 }
 
-export default function SettingsPage() {
+export default function SettingsPage({ billingOnly = false }: { billingOnly?: boolean }) {
   const [settings, setSettings] = useState<NotificationSettings>({
     telegramChatId: null,
     telegramEnabled: false,
@@ -92,24 +118,41 @@ export default function SettingsPage() {
   const [loading, setLoading] = useState(true);
   const [saving, setSaving] = useState(false);
   const [testing, setTesting] = useState<string | null>(null);
+  const [billing, setBilling] = useState<BillingOverview | null>(null);
+  const [billingLoading, setBillingLoading] = useState(true);
+  const [billingAction, setBillingAction] = useState<'checkout' | 'portal' | null>(null);
   const [message, setMessage] = useState<{ type: 'success' | 'error'; text: string } | null>(null);
 
   // Form state for Telegram chat ID (separate from saved settings for editing)
   const [telegramChatId, setTelegramChatId] = useState('');
 
+  const hasScheduledCancellation = Boolean(
+    billing?.subscription.cancelAtPeriodEnd || billing?.subscription.cancelAt
+  );
+
   useEffect(() => {
     async function fetchSettings() {
       try {
-        const res = await fetch('/api/settings/notifications');
-        if (res.ok) {
-          const data = await res.json();
+        const [settingsRes, billingRes] = await Promise.all([
+          fetch('/api/settings/notifications'),
+          fetch('/api/billing'),
+        ]);
+
+        if (settingsRes.ok) {
+          const data = await settingsRes.json();
           setSettings(data.data);
           setTelegramChatId(data.data.telegramChatId || '');
         }
+
+        if (billingRes.ok) {
+          const data = await billingRes.json();
+          setBilling(data.data);
+        }
       } catch {
-        console.error('Failed to fetch notification settings');
+        console.error('Failed to fetch settings');
       } finally {
         setLoading(false);
+        setBillingLoading(false);
       }
     }
     fetchSettings();
@@ -174,6 +217,31 @@ export default function SettingsPage() {
     [telegramChatId, showMessage]
   );
 
+  const handleBillingRedirect = useCallback(
+    async (endpoint: '/api/billing/checkout' | '/api/billing/portal') => {
+      setBillingAction(endpoint.endsWith('checkout') ? 'checkout' : 'portal');
+      try {
+        const res = await fetch(endpoint, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+        });
+        const data = await res.json();
+
+        if (!res.ok) {
+          showMessage('error', data.error || 'Failed to open billing flow');
+          return;
+        }
+
+        window.location.href = data.data.url;
+      } catch {
+        showMessage('error', 'Failed to open billing flow');
+      } finally {
+        setBillingAction(null);
+      }
+    },
+    [showMessage]
+  );
+
   if (loading) {
     return (
       <div className="max-w-2xl mx-auto py-8 px-4 space-y-6">
@@ -212,7 +280,7 @@ export default function SettingsPage() {
       <div className="mb-8">
         <h1 className="text-2xl font-bold tracking-tight">Settings</h1>
         <p className="text-muted-foreground mt-1">
-          Manage your notification preferences
+          {billingOnly ? 'Manage your billing access' : 'Manage your notification preferences'}
         </p>
       </div>
 
@@ -235,6 +303,130 @@ export default function SettingsPage() {
         </div>
       )}
 
+      <Card className="mb-6">
+        <CardHeader>
+          <CardTitle className="flex items-center gap-2">
+            <CreditCard className="h-5 w-5" />
+            Billing
+          </CardTitle>
+          <CardDescription>
+            Manage your paid plan and workspace creation access
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          {billingLoading || !billing ? (
+            <div className="space-y-3">
+              <Skeleton className="h-4 w-40" />
+              <Skeleton className="h-4 w-full" />
+              <Skeleton className="h-10 w-44 rounded-md" />
+            </div>
+          ) : !billing.isConfigured ? (
+            <div className="rounded-md border border-amber-500/30 bg-amber-500/10 p-4 text-sm text-amber-700 dark:text-amber-400">
+              Stripe is not configured yet. Add your Stripe environment variables before using billing.
+            </div>
+          ) : (
+            <>
+              <div className="flex items-center justify-between rounded-lg border p-4">
+                <div>
+                  <p className="text-sm font-medium">Current plan</p>
+                  <p className="text-sm text-muted-foreground mt-1">
+                    {billing.subscription.hasActiveSubscription
+                      ? hasScheduledCancellation
+                        ? billing.subscription.hasActiveTrial
+                          ? 'Trial canceled. Access remains active until the trial ends.'
+                          : 'Subscription canceled. Access remains active until the end of the current billing period.'
+                        : 'Paid account with workspace creation unlocked.'
+                      : billing.subscription.hasActiveTrial
+                        ? 'Trial access is active.'
+                        : 'Billing access has ended.'}
+                  </p>
+                </div>
+                <Badge
+                  variant={billing.subscription.hasActiveSubscription ? 'default' : 'secondary'}
+                >
+                  {billing.subscription.label}
+                </Badge>
+              </div>
+
+              {billing.subscription.hasActiveTrial
+              && billing.subscription.trialEndsAt
+              && hasScheduledCancellation ? (
+                <p
+                  className="rounded-md border border-destructive/30 bg-destructive/10 px-3 py-2 text-sm font-medium text-destructive"
+                >
+                  Access ends on {' '}
+                  {new Date(billing.subscription.trialEndsAt).toLocaleDateString()}.
+                </p>
+              ) : null}
+
+              {billing.subscription.currentPeriodEnd ? (
+                <p className="text-sm text-muted-foreground">
+                  {hasScheduledCancellation ? 'Your subscription ends on ' : 'Current billing period ends on '}
+                  {new Date(billing.subscription.currentPeriodEnd).toLocaleDateString()}.
+                </p>
+              ) : null}
+
+              {hasScheduledCancellation && billing.subscription.cancelAt ? (
+                <p className="text-sm text-muted-foreground">
+                  Cancellation was scheduled on {new Date(billing.subscription.cancelAt).toLocaleDateString()}.
+                </p>
+              ) : null}
+
+              {!billing.subscription.hasBillingAccess
+              && billing.subscription.billingAccessEndedAt
+              && billing.subscription.storageCleanupEligibleAt ? (
+                <p className="text-sm text-amber-700 dark:text-amber-400">
+                  Stored media cleanup is scheduled after {new Date(billing.subscription.storageCleanupEligibleAt).toLocaleDateString()} unless billing is restored first.
+                </p>
+              ) : null}
+
+              <div className="rounded-lg border bg-muted/30 p-4 space-y-2">
+                <p className="text-sm font-medium">Workspace creation</p>
+                <p className="text-sm text-muted-foreground">
+                  {billing.workspaceCreation.canCreateWorkspace
+                    ? 'This account can create workspaces.'
+                    : billing.workspaceCreation.reason || 'Upgrade to create another workspace.'}
+                </p>
+              </div>
+
+              <div className="flex flex-col sm:flex-row gap-3">
+                {billing.subscription.hasActiveSubscription && billing.portalAvailable ? (
+                  <Button
+                    onClick={() => handleBillingRedirect('/api/billing/portal')}
+                    disabled={billingAction !== null}
+                  >
+                    {billingAction === 'portal' ? (
+                      <>
+                        <Loader2 className="h-4 w-4 mr-2 animate-spin" />
+                        Opening Portal...
+                      </>
+                    ) : (
+                      'Manage Subscription'
+                    )}
+                  </Button>
+                ) : (
+                  <Button
+                    onClick={() => handleBillingRedirect('/api/billing/checkout')}
+                    disabled={!billing.checkoutAvailable || billingAction !== null}
+                  >
+                    {billingAction === 'checkout' ? (
+                      <>
+                        <Loader2 className="h-4 w-4 mr-2 animate-spin" />
+                        Redirecting...
+                      </>
+                    ) : (
+                      'Upgrade with Stripe'
+                    )}
+                  </Button>
+                )}
+              </div>
+            </>
+          )}
+        </CardContent>
+      </Card>
+
+      {!billingOnly && (
+        <>
       {/* Event Subscriptions */}
       <Card className="mb-6">
         <CardHeader>
@@ -246,7 +438,7 @@ export default function SettingsPage() {
             Choose which events trigger notifications
           </CardDescription>
         </CardHeader>
-        <CardContent className="space-y-2">
+        <CardContent className="space-y-4">
           <ToggleButton
             enabled={settings.onNewVideo}
             onToggle={() =>
@@ -518,6 +710,8 @@ export default function SettingsPage() {
           )}
         </Button>
       </div>
+        </>
+      )}
     </div>
   );
 }
diff --git a/app/(dashboard)/workspaces/[workspaceId]/page.tsx b/app/(dashboard)/workspaces/[workspaceId]/page.tsx
index ba91b4f..4f10c92 100644
--- a/app/(dashboard)/workspaces/[workspaceId]/page.tsx
+++ b/app/(dashboard)/workspaces/[workspaceId]/page.tsx
@@ -14,7 +14,7 @@ import {
 import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
 import { Badge } from '@/components/ui/badge';
-import { auth } from '@/lib/auth';
+import { auth, checkWorkspaceAccess } from '@/lib/auth';
 import { db } from '@/lib/db';
 import { VideoDragDropUploader } from '@/components/video-drag-drop-uploader';
 
@@ -94,8 +94,9 @@ export default async function WorkspacePage({ params, searchParams }: WorkspaceP
   const membership = workspace.members[0];
   const isMember = !!membership;
   const isAdmin = isOwner || membership?.role === 'ADMIN';
+  const access = await checkWorkspaceAccess({ id: workspace.id, ownerId: workspace.ownerId }, session.user.id);
 
-  if (!isOwner && !isMember) {
+  if (!access.hasAccess || (!isOwner && !isMember)) {
     redirect('/dashboard');
   }
 
diff --git a/app/(dashboard)/workspaces/[workspaceId]/settings/page.tsx b/app/(dashboard)/workspaces/[workspaceId]/settings/page.tsx
index 49db740..1ba9547 100644
--- a/app/(dashboard)/workspaces/[workspaceId]/settings/page.tsx
+++ b/app/(dashboard)/workspaces/[workspaceId]/settings/page.tsx
@@ -8,10 +8,10 @@ interface WorkspaceSettingsPageProps {
 export default async function WorkspaceSettingsPage({ params }: WorkspaceSettingsPageProps) {
   const { workspaceId } = await params;
 
-  await requireWorkspaceAccessOrRedirect({
+  const { access } = await requireWorkspaceAccessOrRedirect({
     workspaceId,
     intent: 'manage',
   });
 
-  return <WorkspaceSettingsPageClient workspaceId={workspaceId} />;
+  return <WorkspaceSettingsPageClient workspaceId={workspaceId} canDelete={access.canDelete} />;
 }
diff --git a/app/(dashboard)/workspaces/[workspaceId]/settings/workspace-settings-page-client.tsx b/app/(dashboard)/workspaces/[workspaceId]/settings/workspace-settings-page-client.tsx
index cd6a337..50150eb 100644
--- a/app/(dashboard)/workspaces/[workspaceId]/settings/workspace-settings-page-client.tsx
+++ b/app/(dashboard)/workspaces/[workspaceId]/settings/workspace-settings-page-client.tsx
@@ -30,7 +30,13 @@ interface WorkspaceData {
   ownerId: string;
 }
 
-export default function WorkspaceSettingsPageClient({ workspaceId }: { workspaceId: string }) {
+export default function WorkspaceSettingsPageClient({
+  workspaceId,
+  canDelete,
+}: {
+  workspaceId: string;
+  canDelete: boolean;
+}) {
   const router = useRouter();
 
   const [workspace, setWorkspace] = useState<WorkspaceData | null>(null);
@@ -202,65 +208,68 @@ export default function WorkspaceSettingsPageClient({ workspaceId }: { workspace
         </CardContent>
       </Card>
 
-      <Separator className="my-8" />
+      {canDelete ? (
+        <>
+          <Separator className="my-8" />
 
-      {/* Danger Zone */}
-      <Card className="border-destructive/50">
-        <CardHeader>
-          <CardTitle className="text-destructive">Danger Zone</CardTitle>
-          <CardDescription>
-            Irreversible actions. Proceed with caution.
-          </CardDescription>
-        </CardHeader>
-        <CardContent>
-          <AlertDialog>
-            <AlertDialogTrigger asChild>
-              <Button variant="destructive">
-                <Trash2 className="h-4 w-4 mr-2" />
-                Delete Workspace
-              </Button>
-            </AlertDialogTrigger>
-            <AlertDialogContent>
-              <AlertDialogHeader>
-                <AlertDialogTitle>Delete &quot;{workspace.name}&quot;?</AlertDialogTitle>
-                <AlertDialogDescription asChild>
-                  <div className="space-y-4">
-                    <p>
-                      This will permanently delete this workspace and everything inside it
-                      (projects, videos, comments, images, and voice notes). This action cannot be undone.
-                    </p>
-                    <div className="space-y-2">
-                      <Label htmlFor="delete-workspace-confirm">
-                        Type <strong className="text-foreground">{workspace.name}</strong> to confirm
-                      </Label>
-                      <Input
-                        id="delete-workspace-confirm"
-                        value={deleteConfirmation}
-                        onChange={(e) => setDeleteConfirmation(e.target.value)}
-                        placeholder="Workspace name"
-                        className="h-11"
-                      />
-                    </div>
-                  </div>
-                </AlertDialogDescription>
-              </AlertDialogHeader>
-              <AlertDialogFooter>
-                <AlertDialogCancel onClick={() => setDeleteConfirmation('')}>
-                  Cancel
-                </AlertDialogCancel>
-                <AlertDialogAction
-                  onClick={handleDelete}
-                  disabled={deleteConfirmation !== workspace.name || isDeleting}
-                  className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
-                >
-                  {isDeleting && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
-                  Delete Workspace
-                </AlertDialogAction>
-              </AlertDialogFooter>
-            </AlertDialogContent>
-          </AlertDialog>
-        </CardContent>
-      </Card>
+          <Card className="border-destructive/50">
+            <CardHeader>
+              <CardTitle className="text-destructive">Danger Zone</CardTitle>
+              <CardDescription>
+                Irreversible actions. Proceed with caution.
+              </CardDescription>
+            </CardHeader>
+            <CardContent>
+              <AlertDialog>
+                <AlertDialogTrigger asChild>
+                  <Button variant="destructive">
+                    <Trash2 className="h-4 w-4 mr-2" />
+                    Delete Workspace
+                  </Button>
+                </AlertDialogTrigger>
+                <AlertDialogContent>
+                  <AlertDialogHeader>
+                    <AlertDialogTitle>Delete &quot;{workspace.name}&quot;?</AlertDialogTitle>
+                    <AlertDialogDescription asChild>
+                      <div className="space-y-4">
+                        <p>
+                          This will permanently delete this workspace and everything inside it
+                          (projects, videos, comments, images, and voice notes). This action cannot be undone.
+                        </p>
+                        <div className="space-y-2">
+                          <Label htmlFor="delete-workspace-confirm">
+                            Type <strong className="text-foreground">{workspace.name}</strong> to confirm
+                          </Label>
+                          <Input
+                            id="delete-workspace-confirm"
+                            value={deleteConfirmation}
+                            onChange={(e) => setDeleteConfirmation(e.target.value)}
+                            placeholder="Workspace name"
+                            className="h-11"
+                          />
+                        </div>
+                      </div>
+                    </AlertDialogDescription>
+                  </AlertDialogHeader>
+                  <AlertDialogFooter>
+                    <AlertDialogCancel onClick={() => setDeleteConfirmation('')}>
+                      Cancel
+                    </AlertDialogCancel>
+                    <AlertDialogAction
+                      onClick={handleDelete}
+                      disabled={deleteConfirmation !== workspace.name || isDeleting}
+                      className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+                    >
+                      {isDeleting && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
+                      Delete Workspace
+                    </AlertDialogAction>
+                  </AlertDialogFooter>
+                </AlertDialogContent>
+              </AlertDialog>
+            </CardContent>
+          </Card>
+        </>
+      ) : null}
     </div>
   );
 }
diff --git a/app/(dashboard)/workspaces/new/new-workspace-page-client.tsx b/app/(dashboard)/workspaces/new/new-workspace-page-client.tsx
index e0c43c9..70a388c 100644
--- a/app/(dashboard)/workspaces/new/new-workspace-page-client.tsx
+++ b/app/(dashboard)/workspaces/new/new-workspace-page-client.tsx
@@ -3,14 +3,21 @@
 import { useState } from 'react';
 import { useRouter } from 'next/navigation';
 import Link from 'next/link';
-import { ArrowLeft, Loader2, Building2 } from 'lucide-react';
+import { ArrowLeft, Loader2, Building2, Lock } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Textarea } from '@/components/ui/textarea';
 
-export default function NewWorkspacePage() {
+export default function NewWorkspacePage({
+  workspaceCreation,
+}: {
+  workspaceCreation: {
+    canCreateWorkspace: boolean;
+    reason: string | null;
+  };
+}) {
   const router = useRouter();
   const [isLoading, setIsLoading] = useState(false);
   const [error, setError] = useState('');
@@ -62,65 +69,84 @@ export default function NewWorkspacePage() {
         <Card className="border-border/50 shadow-lg">
           <CardHeader className="text-center pb-2">
             <div className="mx-auto w-14 h-14 rounded-full bg-primary/10 flex items-center justify-center mb-4">
-              <Building2 className="h-7 w-7 text-primary" />
+              {workspaceCreation.canCreateWorkspace ? (
+                <Building2 className="h-7 w-7 text-primary" />
+              ) : (
+                <Lock className="h-7 w-7 text-primary" />
+              )}
             </div>
-            <CardTitle className="text-2xl">Create New Workspace</CardTitle>
+            <CardTitle className="text-2xl">
+              {workspaceCreation.canCreateWorkspace ? 'Create New Workspace' : 'Upgrade Required'}
+            </CardTitle>
             <CardDescription className="text-base">
-              Set up a workspace to organize projects and invite your team
+              {workspaceCreation.canCreateWorkspace
+                ? 'Set up a workspace to organize projects and invite your team'
+                : workspaceCreation.reason || 'Upgrade your account to create another workspace.'}
             </CardDescription>
           </CardHeader>
           <CardContent className="pt-6">
-            <form onSubmit={handleSubmit} className="space-y-6">
-              <div className="space-y-2">
-                <Label htmlFor="name" className="text-sm font-medium">
-                  Workspace Name
-                </Label>
-                <Input
-                  id="name"
-                  placeholder="e.g., My Studio"
-                  value={formData.name}
-                  onChange={(e) =>
-                    setFormData({ ...formData, name: e.target.value })
-                  }
-                  required
-                  disabled={isLoading}
-                />
-              </div>
-
-              <div className="space-y-2">
-                <Label htmlFor="description" className="text-sm font-medium">
-                  Description{' '}
-                  <span className="text-muted-foreground font-normal">(optional)</span>
-                </Label>
-                <Textarea
-                  id="description"
-                  placeholder="What is this workspace for?"
-                  value={formData.description}
-                  onChange={(e) =>
-                    setFormData({ ...formData, description: e.target.value })
-                  }
-                  rows={3}
-                  disabled={isLoading}
-                />
-              </div>
-
-              {error && (
-                <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive">
-                  {error}
+            {workspaceCreation.canCreateWorkspace ? (
+              <form onSubmit={handleSubmit} className="space-y-6">
+                <div className="space-y-2">
+                  <Label htmlFor="name" className="text-sm font-medium">
+                    Workspace Name
+                  </Label>
+                  <Input
+                    id="name"
+                    placeholder="e.g., My Studio"
+                    value={formData.name}
+                    onChange={(e) =>
+                      setFormData({ ...formData, name: e.target.value })
+                    }
+                    required
+                    disabled={isLoading}
+                  />
                 </div>
-              )}
 
-              <Button type="submit" className="w-full" disabled={isLoading}>
-                {isLoading ? (
-                  <>
-                    <Loader2 className="h-4 w-4 mr-2 animate-spin" />
-                    Creating...
-                  </>
-                ) : (
-                  'Create Workspace'
+                <div className="space-y-2">
+                  <Label htmlFor="description" className="text-sm font-medium">
+                    Description{' '}
+                    <span className="text-muted-foreground font-normal">(optional)</span>
+                  </Label>
+                  <Textarea
+                    id="description"
+                    placeholder="What is this workspace for?"
+                    value={formData.description}
+                    onChange={(e) =>
+                      setFormData({ ...formData, description: e.target.value })
+                    }
+                    rows={3}
+                    disabled={isLoading}
+                  />
+                </div>
+
+                {error && (
+                  <div className="rounded-md bg-destructive/10 p-3 text-sm text-destructive">
+                    {error}
+                  </div>
                 )}
-              </Button>
-            </form>
+
+                <Button type="submit" className="w-full" disabled={isLoading}>
+                  {isLoading ? (
+                    <>
+                      <Loader2 className="h-4 w-4 mr-2 animate-spin" />
+                      Creating...
+                    </>
+                  ) : (
+                    'Create Workspace'
+                  )}
+                </Button>
+              </form>
+            ) : (
+              <div className="space-y-2">
+                <p className="text-sm text-muted-foreground">
+                  You can still create and manage projects inside workspaces where you are already a member.
+                </p>
+                <Button asChild className="w-full">
+                  <Link href="/settings">Open Billing Settings</Link>
+                </Button>
+              </div>
+            )}
           </CardContent>
         </Card>
       </div>
diff --git a/app/(dashboard)/workspaces/new/page.tsx b/app/(dashboard)/workspaces/new/page.tsx
index c119dfa..d886631 100644
--- a/app/(dashboard)/workspaces/new/page.tsx
+++ b/app/(dashboard)/workspaces/new/page.tsx
@@ -1,7 +1,14 @@
 import { requireAuthOrRedirect } from '@/lib/route-access';
+import { getBillingOverview } from '@/lib/billing';
 import NewWorkspacePageClient from './new-workspace-page-client';
 
 export default async function NewWorkspacePage() {
-  await requireAuthOrRedirect();
-  return <NewWorkspacePageClient />;
+  const session = await requireAuthOrRedirect();
+  if (!session?.user?.id) {
+    return null;
+  }
+
+  const billing = await getBillingOverview(session.user.id);
+
+  return <NewWorkspacePageClient workspaceCreation={billing.workspaceCreation} />;
 }
diff --git a/app/(dashboard)/workspaces/page.tsx b/app/(dashboard)/workspaces/page.tsx
index a0a6c7c..2916859 100644
--- a/app/(dashboard)/workspaces/page.tsx
+++ b/app/(dashboard)/workspaces/page.tsx
@@ -1,6 +1,8 @@
 import { auth } from '@/lib/auth';
 import { redirect } from 'next/navigation';
 import { db } from '@/lib/db';
+import { buildBillingAccessWhereInput, getBillingOverview } from '@/lib/billing';
+import { hasCollaboratorBillingBackedAccess, requireBillingAccessOrRedirect } from '@/lib/route-access';
 import { WorkspacesClient } from './workspaces-client';
 
 export default async function WorkspacesPage({
@@ -13,19 +15,24 @@ export default async function WorkspacesPage({
     redirect('/login');
   }
 
+  const hasCollaboratorAccess = await hasCollaboratorBillingBackedAccess(session.user.id);
+  if (!hasCollaboratorAccess) {
+    await requireBillingAccessOrRedirect({ userId: session.user.id });
+  }
+
   const resolvedSearchParams = await searchParams;
   const page = Number(resolvedSearchParams?.page) || 1;
   const pageSize = 20;
   const skip = (page - 1) * pageSize;
 
-  const [workspaces, totalWorkspaces] = await Promise.all([
+  const [workspaces, totalWorkspaces, billing] = await Promise.all([
     db.workspace.findMany({
       skip,
       take: pageSize,
       where: {
         OR: [
-          { ownerId: session.user.id },
-          { members: { some: { userId: session.user.id } } },
+          { ownerId: session.user.id, owner: buildBillingAccessWhereInput() },
+          { members: { some: { userId: session.user.id } }, owner: buildBillingAccessWhereInput() },
         ],
       },
       include: {
@@ -42,11 +49,12 @@ export default async function WorkspacesPage({
     db.workspace.count({
       where: {
         OR: [
-          { ownerId: session.user.id },
-          { members: { some: { userId: session.user.id } } },
+          { ownerId: session.user.id, owner: buildBillingAccessWhereInput() },
+          { members: { some: { userId: session.user.id } }, owner: buildBillingAccessWhereInput() },
         ],
       }
-    })
+    }),
+    getBillingOverview(session.user.id),
   ]);
 
   const totalPages = Math.ceil(totalWorkspaces / pageSize);
@@ -60,6 +68,11 @@ export default async function WorkspacesPage({
   }));
 
   return (
-    <WorkspacesClient workspaces={serializedWorkspaces} totalPages={totalPages} currentPage={page} />
+    <WorkspacesClient
+      workspaces={serializedWorkspaces}
+      totalPages={totalPages}
+      currentPage={page}
+      workspaceCreation={billing.workspaceCreation}
+    />
   );
 }
diff --git a/app/(dashboard)/workspaces/workspaces-client.tsx b/app/(dashboard)/workspaces/workspaces-client.tsx
index 6b3ad0e..cbf36bd 100644
--- a/app/(dashboard)/workspaces/workspaces-client.tsx
+++ b/app/(dashboard)/workspaces/workspaces-client.tsx
@@ -35,9 +35,18 @@ interface WorkspacesClientProps {
   workspaces: SerializedWorkspace[];
   totalPages: number;
   currentPage: number;
+  workspaceCreation: {
+    canCreateWorkspace: boolean;
+    reason: string | null;
+  };
 }
 
-export function WorkspacesClient({ workspaces, totalPages, currentPage }: WorkspacesClientProps) {
+export function WorkspacesClient({
+  workspaces,
+  totalPages,
+  currentPage,
+  workspaceCreation,
+}: WorkspacesClientProps) {
   const router = useRouter();
 
   return (
@@ -49,13 +58,26 @@ export function WorkspacesClient({ workspaces, totalPages, currentPage }: Worksp
           <p className="text-muted-foreground mt-1">
             Manage your workspaces and their projects
           </p>
+          {!workspaceCreation.canCreateWorkspace && workspaceCreation.reason ? (
+            <p className="text-sm text-amber-700 dark:text-amber-400 mt-2">
+              {workspaceCreation.reason}
+            </p>
+          ) : null}
         </div>
-        <Button asChild className="w-full sm:w-auto">
-          <Link href="/workspaces/new">
-            <Plus className="h-4 w-4 mr-2" />
-            New Workspace
-          </Link>
-        </Button>
+        {workspaceCreation.canCreateWorkspace ? (
+          <Button asChild className="w-full sm:w-auto">
+            <Link href="/workspaces/new">
+              <Plus className="h-4 w-4 mr-2" />
+              New Workspace
+            </Link>
+          </Button>
+        ) : (
+          <Button asChild className="w-full sm:w-auto">
+            <Link href="/settings">
+              Upgrade to Create Workspace
+            </Link>
+          </Button>
+        )}
       </div>
 
       {/* Workspaces Grid */}
@@ -101,12 +123,18 @@ export function WorkspacesClient({ workspaces, totalPages, currentPage }: Worksp
             <p className="text-muted-foreground text-center mb-4">
               Create a workspace to organize your projects and invite team members
             </p>
-            <Button asChild>
-              <Link href="/workspaces/new">
-                <Plus className="h-4 w-4 mr-2" />
-                Create Workspace
-              </Link>
-            </Button>
+            {workspaceCreation.canCreateWorkspace ? (
+              <Button asChild>
+                <Link href="/workspaces/new">
+                  <Plus className="h-4 w-4 mr-2" />
+                  Create Workspace
+                </Link>
+              </Button>
+            ) : (
+              <Button asChild>
+                <Link href="/settings">Upgrade to Create Workspace</Link>
+              </Button>
+            )}
           </CardContent>
         </Card>
       )}
diff --git a/app/admin/layout.tsx b/app/admin/layout.tsx
index 991263d..e34bd9c 100644
--- a/app/admin/layout.tsx
+++ b/app/admin/layout.tsx
@@ -17,7 +17,7 @@ export default async function AdminLayout({
 
     return (
         <div className="relative flex min-h-screen flex-col">
-            <Header user={session.user} />
+            <Header user={session.user} showAppNavigation />
             <div className="w-full px-4 md:px-8 flex-1 items-start md:grid md:grid-cols-[220px_minmax(0,1fr)] md:gap-6 lg:grid-cols-[240px_minmax(0,1fr)] lg:gap-10">
                 {/* Mobile Nav */}
                 <div className="md:hidden py-4 border-b mb-4">
diff --git a/app/api/billing/checkout/route.ts b/app/api/billing/checkout/route.ts
new file mode 100644
index 0000000..60c657a
--- /dev/null
+++ b/app/api/billing/checkout/route.ts
@@ -0,0 +1,80 @@
+import { NextRequest } from 'next/server';
+import { auth } from '@/lib/auth';
+import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
+import {
+  DEFAULT_TRIAL_PERIOD_DAYS,
+  getOrCreateStripeCustomerId,
+  getStripeCheckoutState,
+} from '@/lib/billing';
+import { rateLimit } from '@/lib/rate-limit';
+import { getStripe, getStripePriceId, isStripeConfigured } from '@/lib/stripe';
+import { isTrustedSameOriginRequest } from '@/lib/request-origin';
+
+function getAppOrigin(request: NextRequest) {
+  if (isTrustedSameOriginRequest(request)) {
+    const origin = request.headers.get('origin');
+    if (origin) {
+      return new URL(origin).origin;
+    }
+  }
+
+  return request.nextUrl.origin;
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const limited = await rateLimit(request, 'mutate');
+    if (limited) return limited;
+
+    if (!isTrustedSameOriginRequest(request)) {
+      return apiErrors.forbidden('Invalid request origin');
+    }
+
+    const session = await auth();
+    if (!session?.user?.id) {
+      return apiErrors.unauthorized();
+    }
+
+    if (!isStripeConfigured()) {
+      return apiErrors.internalError('Stripe billing is not configured');
+    }
+
+    const checkoutState = await getStripeCheckoutState(session.user.id);
+    if (checkoutState.hasActiveSubscription) {
+      return apiErrors.badRequest('An active subscription already exists for this account');
+    }
+
+    const stripe = getStripe();
+    const priceId = getStripePriceId();
+    const customerId = await getOrCreateStripeCustomerId(session.user.id);
+    const appOrigin = getAppOrigin(request);
+
+    const checkoutSession = await stripe.checkout.sessions.create({
+      mode: 'subscription',
+      customer: customerId,
+      line_items: [{ price: priceId, quantity: 1 }],
+      allow_promotion_codes: true,
+      success_url: `${appOrigin}/settings?billing=success`,
+      cancel_url: `${appOrigin}/settings?billing=canceled`,
+      metadata: {
+        userId: session.user.id,
+      },
+      subscription_data: {
+        metadata: {
+          userId: session.user.id,
+        },
+        ...(checkoutState.isTrialEligible ? { trial_period_days: DEFAULT_TRIAL_PERIOD_DAYS } : {}),
+      },
+    });
+
+    if (!checkoutSession.url) {
+      throw new Error('Stripe did not return a checkout URL');
+    }
+
+    const response = successResponse({ url: checkoutSession.url });
+    return withCacheControl(response, 'private, no-store');
+  } catch (error) {
+    console.error('Error creating Stripe checkout session:', error);
+    return apiErrors.internalError('Failed to start checkout');
+  }
+}
diff --git a/app/api/billing/portal/route.ts b/app/api/billing/portal/route.ts
new file mode 100644
index 0000000..8e230d7
--- /dev/null
+++ b/app/api/billing/portal/route.ts
@@ -0,0 +1,55 @@
+import { NextRequest } from 'next/server';
+import { auth } from '@/lib/auth';
+import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
+import { getBillingOverview } from '@/lib/billing';
+import { rateLimit } from '@/lib/rate-limit';
+import { getStripe, isStripeConfigured } from '@/lib/stripe';
+import { isTrustedSameOriginRequest } from '@/lib/request-origin';
+
+function getAppOrigin(request: NextRequest) {
+  if (isTrustedSameOriginRequest(request)) {
+    const origin = request.headers.get('origin');
+    if (origin) {
+      return new URL(origin).origin;
+    }
+  }
+
+  return request.nextUrl.origin;
+}
+
+export async function POST(request: NextRequest) {
+  try {
+    const limited = await rateLimit(request, 'mutate');
+    if (limited) return limited;
+
+    if (!isTrustedSameOriginRequest(request)) {
+      return apiErrors.forbidden('Invalid request origin');
+    }
+
+    const session = await auth();
+    if (!session?.user?.id) {
+      return apiErrors.unauthorized();
+    }
+
+    if (!isStripeConfigured()) {
+      return apiErrors.internalError('Stripe billing is not configured');
+    }
+
+    const billing = await getBillingOverview(session.user.id);
+    if (!billing.subscription.stripeCustomerId) {
+      return apiErrors.badRequest('No Stripe customer exists for this account');
+    }
+
+    const stripe = getStripe();
+    const portalSession = await stripe.billingPortal.sessions.create({
+      customer: billing.subscription.stripeCustomerId,
+      return_url: `${getAppOrigin(request)}/settings`,
+    });
+
+    const response = successResponse({ url: portalSession.url });
+    return withCacheControl(response, 'private, no-store');
+  } catch (error) {
+    console.error('Error creating Stripe portal session:', error);
+    return apiErrors.internalError('Failed to open billing portal');
+  }
+}
diff --git a/app/api/billing/route.ts b/app/api/billing/route.ts
new file mode 100644
index 0000000..636ab3b
--- /dev/null
+++ b/app/api/billing/route.ts
@@ -0,0 +1,40 @@
+import { auth } from '@/lib/auth';
+import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
+import { getBillingOverview } from '@/lib/billing';
+import { isStripeConfigured } from '@/lib/stripe';
+
+export async function GET() {
+  try {
+    const session = await auth();
+    if (!session?.user?.id) {
+      return apiErrors.unauthorized();
+    }
+
+    const billing = await getBillingOverview(session.user.id);
+    const response = successResponse({
+      isConfigured: isStripeConfigured(),
+      checkoutAvailable: isStripeConfigured() && !billing.subscription.hasActiveSubscription,
+      portalAvailable: isStripeConfigured() && Boolean(billing.subscription.stripeCustomerId),
+      subscription: {
+        status: billing.subscription.status,
+        label: billing.subscription.label,
+        hasActiveSubscription: billing.subscription.hasActiveSubscription,
+        hasActiveTrial: billing.subscription.hasActiveTrial,
+        hasBillingAccess: billing.subscription.hasBillingAccess,
+        priceId: billing.subscription.stripePriceId,
+        currentPeriodEnd: billing.subscription.currentPeriodEnd?.toISOString() ?? null,
+        cancelAtPeriodEnd: billing.subscription.cancelAtPeriodEnd ?? false,
+        cancelAt: billing.subscription.cancelAt?.toISOString() ?? null,
+        trialEndsAt: billing.subscription.trialEndsAt?.toISOString() ?? null,
+        billingAccessEndedAt: billing.subscription.billingAccessEndedAt?.toISOString() ?? null,
+        storageCleanupEligibleAt: billing.subscription.storageCleanupEligibleAt?.toISOString() ?? null,
+      },
+      workspaceCreation: billing.workspaceCreation,
+    });
+
+    return withCacheControl(response, 'private, no-store');
+  } catch (error) {
+    console.error('Error fetching billing overview:', error);
+    return apiErrors.internalError('Failed to fetch billing overview');
+  }
+}
diff --git a/app/api/projects/[projectId]/members/[memberId]/route.ts b/app/api/projects/[projectId]/members/[memberId]/route.ts
index 8510338..292b86d 100644
--- a/app/api/projects/[projectId]/members/[memberId]/route.ts
+++ b/app/api/projects/[projectId]/members/[memberId]/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
-import { auth } from '@/lib/auth';
+import { auth, checkProjectAccess } from '@/lib/auth';
 import { ProjectMemberRole } from '@prisma/client';
 import { rateLimit } from '@/lib/rate-limit';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
@@ -29,10 +29,11 @@ export async function PATCH(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Project');
         }
 
+        const access = await checkProjectAccess(project, session.user.id, { intent: 'manage' });
         const isOwner = project.ownerId === session.user.id;
         const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
 
-        if (!isOwner && !isAdmin) {
+        if (!access.canEdit || (!isOwner && !isAdmin)) {
             return apiErrors.forbidden('Access denied');
         }
 
@@ -44,15 +45,24 @@ export async function PATCH(request: NextRequest, { params }: RouteParams) {
             return apiErrors.badRequest('Invalid role. Must be ADMIN or COMMENTATOR.');
         }
 
-        const member = await db.projectMember.update({
-            where: { id: memberId },
+        const member = await db.projectMember.findFirst({
+            where: { id: memberId, projectId },
+            select: { id: true },
+        });
+
+        if (!member) {
+            return apiErrors.notFound('Member');
+        }
+
+        const updatedMember = await db.projectMember.update({
+            where: { id: member.id },
             data: { role: role as ProjectMemberRole },
             include: {
                 user: { select: { id: true, name: true, image: true } },
             },
         });
 
-        const response = successResponse(member);
+        const response = successResponse(updatedMember);
         return withCacheControl(response, 'private, no-store');
     } catch (error) {
         console.error('Error updating member role:', error);
@@ -82,11 +92,13 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Project');
         }
 
+        const access = await checkProjectAccess(project, session.user.id, { intent: 'manage' });
         const isOwner = project.ownerId === session.user.id;
         const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
 
-        const memberToRemove = await db.projectMember.findUnique({
-            where: { id: memberId },
+        const memberToRemove = await db.projectMember.findFirst({
+            where: { id: memberId, projectId },
+            select: { id: true, userId: true },
         });
 
         if (!memberToRemove) {
@@ -95,11 +107,11 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
 
         const isSelf = memberToRemove.userId === session.user.id;
 
-        if (!isOwner && !isAdmin && !isSelf) {
+        if ((!access.canEdit || (!isOwner && !isAdmin)) && !isSelf) {
             return apiErrors.forbidden('Access denied');
         }
 
-        await db.projectMember.delete({ where: { id: memberId } });
+        await db.projectMember.delete({ where: { id: memberToRemove.id } });
 
         const response = successResponse({ message: 'Member removed' });
         return withCacheControl(response, 'private, no-store');
diff --git a/app/api/projects/[projectId]/members/invitations/[invitationId]/route.ts b/app/api/projects/[projectId]/members/invitations/[invitationId]/route.ts
index 6dd0dcb..f2f4dd6 100644
--- a/app/api/projects/[projectId]/members/invitations/[invitationId]/route.ts
+++ b/app/api/projects/[projectId]/members/invitations/[invitationId]/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { InvitationStatus, ProjectMemberRole } from '@prisma/client';
-import { auth } from '@/lib/auth';
+import { auth, checkProjectAccess } from '@/lib/auth';
 import { db } from '@/lib/db';
 import { rateLimit } from '@/lib/rate-limit';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
@@ -29,10 +29,11 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
       return apiErrors.notFound('Project');
     }
 
+    const access = await checkProjectAccess(project, session.user.id, { intent: 'manage' });
     const isOwner = project.ownerId === session.user.id;
     const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
 
-    if (!isOwner && !isAdmin) {
+    if (!access.canEdit || (!isOwner && !isAdmin)) {
       return apiErrors.forbidden('Only project owners and admins can cancel invitations');
     }
 
diff --git a/app/api/projects/[projectId]/members/route.ts b/app/api/projects/[projectId]/members/route.ts
index eb7bef1..d936b79 100644
--- a/app/api/projects/[projectId]/members/route.ts
+++ b/app/api/projects/[projectId]/members/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
-import { auth } from '@/lib/auth';
+import { auth, checkProjectAccess } from '@/lib/auth';
 import { InvitationRole, ProjectMemberRole } from '@prisma/client';
 import { rateLimit } from '@/lib/rate-limit';
 import { buildInvitationUrl, createOrRefreshInvitation, sendInvitationEmail } from '@/lib/invitations';
@@ -29,11 +29,12 @@ export async function GET(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Project');
         }
 
+        const access = await checkProjectAccess(project, session.user.id);
         const isOwner = project.ownerId === session.user.id;
         const isMember = project.members.length > 0;
         const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
 
-        if (!isOwner && !isMember) {
+        if (!access.hasAccess || (!isOwner && !isMember)) {
             return apiErrors.forbidden('Access denied');
         }
 
@@ -105,10 +106,11 @@ export async function POST(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Project');
         }
 
+        const access = await checkProjectAccess(project, session.user.id, { intent: 'manage' });
         const isOwner = project.ownerId === session.user.id;
         const isAdmin = project.members[0]?.role === ProjectMemberRole.ADMIN;
 
-        if (!isOwner && !isAdmin) {
+        if (!access.canEdit || (!isOwner && !isAdmin)) {
             return apiErrors.forbidden('Only project owners and admins can invite members');
         }
 
diff --git a/app/api/projects/route.ts b/app/api/projects/route.ts
index 1ebc8e2..06951f2 100644
--- a/app/api/projects/route.ts
+++ b/app/api/projects/route.ts
@@ -1,8 +1,9 @@
 import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
-import { auth } from '@/lib/auth';
+import { auth, checkWorkspaceAccess } from '@/lib/auth';
 import { ProjectVisibility } from '@prisma/client';
 import { rateLimit } from '@/lib/rate-limit';
+import { buildBillingAccessWhereInput } from '@/lib/billing';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
 import { DEFAULT_COMMENT_TAGS } from '@/lib/comment-tags';
 
@@ -48,10 +49,14 @@ export async function GET(request: NextRequest) {
                 // Also include projects in workspaces where the user is a workspace member
                 ...(workspaceId ? [] : [{
                     workspace: {
+                        owner: buildBillingAccessWhereInput(),
                         members: { some: { userId: session.user.id } },
                     },
                 }]),
             ],
+            workspace: {
+                owner: buildBillingAccessWhereInput(),
+            },
         };
 
         // Filter by workspace if provided
@@ -150,10 +155,12 @@ export async function POST(request: NextRequest) {
             return apiErrors.notFound('Workspace');
         }
 
-        const isWsOwner = workspace.ownerId === session.user.id;
-        const isWsAdmin = workspace.members[0]?.role === 'ADMIN';
+        const access = await checkWorkspaceAccess(
+            { id: workspace.id, ownerId: workspace.ownerId },
+            session.user.id
+        );
 
-        if (!isWsOwner && !isWsAdmin) {
+        if (!access.canEdit) {
             return apiErrors.forbidden('Only workspace owners and admins can create projects');
         }
 
@@ -164,7 +171,7 @@ export async function POST(request: NextRequest) {
                     description: description?.trim() || null,
                     slug,
                     visibility: visibility || ProjectVisibility.PRIVATE,
-                    ownerId: session.user.id,
+                    ownerId: workspace.ownerId,
                     workspaceId,
                 },
                 include: {
diff --git a/app/api/stripe/webhook/route.ts b/app/api/stripe/webhook/route.ts
new file mode 100644
index 0000000..7e118fe
--- /dev/null
+++ b/app/api/stripe/webhook/route.ts
@@ -0,0 +1,88 @@
+import { NextRequest } from 'next/server';
+import type Stripe from 'stripe';
+import {
+  markSubscriptionCanceledByCustomerId,
+  syncStripeSubscriptionToUser,
+} from '@/lib/billing';
+import { getStripe, getStripeWebhookSecret } from '@/lib/stripe';
+
+export const runtime = 'nodejs';
+
+async function handleSubscriptionDeleted(subscription: Stripe.Subscription) {
+  const customerId =
+    typeof subscription.customer === 'string'
+      ? subscription.customer
+      : subscription.customer.id;
+
+  const currentPeriodEnd =
+    'current_period_end' in subscription && typeof subscription.current_period_end === 'number'
+      ? new Date(subscription.current_period_end * 1000)
+      : null;
+  const endedAt =
+    'ended_at' in subscription && typeof subscription.ended_at === 'number'
+      ? new Date(subscription.ended_at * 1000)
+      : currentPeriodEnd;
+
+  await markSubscriptionCanceledByCustomerId(customerId, {
+    currentPeriodEnd,
+    endedAt,
+  });
+}
+
+export async function POST(request: NextRequest) {
+  const signature = request.headers.get('stripe-signature');
+  if (!signature) {
+    return new Response('Missing Stripe signature', { status: 400 });
+  }
+
+  let event: Stripe.Event;
+
+  try {
+    const stripe = getStripe();
+    const body = await request.text();
+    event = stripe.webhooks.constructEvent(body, signature, getStripeWebhookSecret());
+  } catch (error) {
+    console.error('Failed to verify Stripe webhook:', error);
+    return new Response('Invalid webhook signature', { status: 400 });
+  }
+
+  try {
+    const stripe = getStripe();
+
+    switch (event.type) {
+      case 'checkout.session.completed': {
+        const session = event.data.object as Stripe.Checkout.Session;
+        if (session.mode === 'subscription' && session.subscription) {
+          const subscriptionId =
+            typeof session.subscription === 'string'
+              ? session.subscription
+              : session.subscription.id;
+          const subscription = await stripe.subscriptions.retrieve(subscriptionId);
+          await syncStripeSubscriptionToUser(subscription);
+        }
+        break;
+      }
+      case 'customer.subscription.created':
+      case 'customer.subscription.updated': {
+        const subscription = event.data.object as Stripe.Subscription;
+        await syncStripeSubscriptionToUser(subscription);
+        break;
+      }
+      case 'customer.subscription.deleted': {
+        const subscription = event.data.object as Stripe.Subscription;
+        await handleSubscriptionDeleted(subscription);
+        break;
+      }
+      default:
+        break;
+    }
+
+    return new Response(JSON.stringify({ received: true }), {
+      status: 200,
+      headers: { 'Content-Type': 'application/json' },
+    });
+  } catch (error) {
+    console.error('Failed to process Stripe webhook:', error);
+    return new Response('Webhook processing failed', { status: 500 });
+  }
+}
diff --git a/app/api/workspaces/[workspaceId]/members/[memberId]/route.ts b/app/api/workspaces/[workspaceId]/members/[memberId]/route.ts
index 9ac0423..203e44d 100644
--- a/app/api/workspaces/[workspaceId]/members/[memberId]/route.ts
+++ b/app/api/workspaces/[workspaceId]/members/[memberId]/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
-import { auth } from '@/lib/auth';
+import { auth, checkWorkspaceAccess } from '@/lib/auth';
 import { WorkspaceMemberRole } from '@prisma/client';
 import { rateLimit } from '@/lib/rate-limit';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
@@ -30,10 +30,14 @@ export async function PATCH(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Workspace');
         }
 
+        const access = await checkWorkspaceAccess(
+            { id: workspace.id, ownerId: workspace.ownerId },
+            session.user.id
+        );
         const isOwner = workspace.ownerId === session.user.id;
         const isAdmin = workspace.members[0]?.role === WorkspaceMemberRole.ADMIN;
 
-        if (!isOwner && !isAdmin) {
+        if (!access.canEdit || (!isOwner && !isAdmin)) {
             return apiErrors.forbidden('Access denied');
         }
 
@@ -45,15 +49,24 @@ export async function PATCH(request: NextRequest, { params }: RouteParams) {
             return apiErrors.badRequest('Invalid role. Must be ADMIN or COMMENTATOR.');
         }
 
-        const member = await db.workspaceMember.update({
-            where: { id: memberId },
+        const member = await db.workspaceMember.findFirst({
+            where: { id: memberId, workspaceId },
+            select: { id: true },
+        });
+
+        if (!member) {
+            return apiErrors.notFound('Member');
+        }
+
+        const updatedMember = await db.workspaceMember.update({
+            where: { id: member.id },
             data: { role: role as WorkspaceMemberRole },
             include: {
                 user: { select: { id: true, name: true, image: true } },
             },
         });
 
-        const response = successResponse(member);
+        const response = successResponse(updatedMember);
         return withCacheControl(response, 'private, no-store');
     } catch (error) {
         console.error('Error updating member role:', error);
@@ -83,12 +96,17 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Workspace');
         }
 
+        const access = await checkWorkspaceAccess(
+            { id: workspace.id, ownerId: workspace.ownerId },
+            session.user.id
+        );
         const isOwner = workspace.ownerId === session.user.id;
         const isAdmin = workspace.members[0]?.role === WorkspaceMemberRole.ADMIN;
 
         // Users can remove themselves, admins/owners can remove anyone
-        const memberToRemove = await db.workspaceMember.findUnique({
-            where: { id: memberId },
+        const memberToRemove = await db.workspaceMember.findFirst({
+            where: { id: memberId, workspaceId },
+            select: { id: true, userId: true },
         });
 
         if (!memberToRemove) {
@@ -97,11 +115,32 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
 
         const isSelf = memberToRemove.userId === session.user.id;
 
-        if (!isOwner && !isAdmin && !isSelf) {
+        if ((!access.canEdit || (!isOwner && !isAdmin)) && !isSelf) {
             return apiErrors.forbidden('Access denied');
         }
 
-        await db.workspaceMember.delete({ where: { id: memberId } });
+        await db.$transaction(async (tx) => {
+            await tx.projectMember.deleteMany({
+                where: {
+                    userId: memberToRemove.userId,
+                    project: {
+                        workspaceId,
+                    },
+                },
+            });
+
+            await tx.project.updateMany({
+                where: {
+                    workspaceId,
+                    ownerId: memberToRemove.userId,
+                },
+                data: {
+                    ownerId: workspace.ownerId,
+                },
+            });
+
+            await tx.workspaceMember.delete({ where: { id: memberToRemove.id } });
+        });
 
         const response = successResponse({ message: 'Member removed' });
         return withCacheControl(response, 'private, no-store');
diff --git a/app/api/workspaces/[workspaceId]/members/invitations/[invitationId]/route.ts b/app/api/workspaces/[workspaceId]/members/invitations/[invitationId]/route.ts
index e512c55..3546d24 100644
--- a/app/api/workspaces/[workspaceId]/members/invitations/[invitationId]/route.ts
+++ b/app/api/workspaces/[workspaceId]/members/invitations/[invitationId]/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { InvitationStatus, WorkspaceMemberRole } from '@prisma/client';
-import { auth } from '@/lib/auth';
+import { auth, checkWorkspaceAccess } from '@/lib/auth';
 import { db } from '@/lib/db';
 import { rateLimit } from '@/lib/rate-limit';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
@@ -29,10 +29,14 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
       return apiErrors.notFound('Workspace');
     }
 
+    const access = await checkWorkspaceAccess(
+      { id: workspace.id, ownerId: workspace.ownerId },
+      session.user.id
+    );
     const isOwner = workspace.ownerId === session.user.id;
     const isAdmin = workspace.members[0]?.role === WorkspaceMemberRole.ADMIN;
 
-    if (!isOwner && !isAdmin) {
+    if (!access.canEdit || (!isOwner && !isAdmin)) {
       return apiErrors.forbidden('Only workspace owners and admins can cancel invitations');
     }
 
diff --git a/app/api/workspaces/[workspaceId]/members/route.ts b/app/api/workspaces/[workspaceId]/members/route.ts
index 965c664..10ccf61 100644
--- a/app/api/workspaces/[workspaceId]/members/route.ts
+++ b/app/api/workspaces/[workspaceId]/members/route.ts
@@ -1,6 +1,6 @@
 import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
-import { auth } from '@/lib/auth';
+import { auth, checkWorkspaceAccess } from '@/lib/auth';
 import { InvitationRole, WorkspaceMemberRole } from '@prisma/client';
 import { rateLimit } from '@/lib/rate-limit';
 import { buildInvitationUrl, createOrRefreshInvitation, sendInvitationEmail } from '@/lib/invitations';
@@ -53,11 +53,15 @@ export async function GET(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Workspace');
         }
 
+        const access = await checkWorkspaceAccess(
+            { id: workspace.id, ownerId: workspace.ownerId },
+            session.user.id
+        );
         const isOwner = workspace.ownerId === session.user.id;
         const isMember = workspace.members.length > 0;
         const isAdmin = workspace.members[0]?.role === WorkspaceMemberRole.ADMIN;
 
-        if (!isOwner && !isMember) {
+        if (!access.hasAccess || (!isOwner && !isMember)) {
             return apiErrors.forbidden('Access denied');
         }
 
@@ -145,10 +149,14 @@ export async function POST(request: NextRequest, { params }: RouteParams) {
             return apiErrors.notFound('Workspace');
         }
 
+        const access = await checkWorkspaceAccess(
+            { id: workspace.id, ownerId: workspace.ownerId },
+            session.user.id
+        );
         const isOwner = workspace.ownerId === session.user.id;
         const isAdmin = workspace.members[0]?.role === WorkspaceMemberRole.ADMIN;
 
-        if (!isOwner && !isAdmin) {
+        if (!access.canEdit || (!isOwner && !isAdmin)) {
             return apiErrors.forbidden('Only workspace owners and admins can invite members');
         }
 
diff --git a/app/api/workspaces/route.ts b/app/api/workspaces/route.ts
index d5f77e7..f6b5d6a 100644
--- a/app/api/workspaces/route.ts
+++ b/app/api/workspaces/route.ts
@@ -2,6 +2,7 @@ import { NextRequest } from 'next/server';
 import { db } from '@/lib/db';
 import { auth } from '@/lib/auth';
 import { rateLimit } from '@/lib/rate-limit';
+import { buildBillingAccessWhereInput, getWorkspaceCreationEligibility } from '@/lib/billing';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
 
 // GET /api/workspaces - List all workspaces for the authenticated user
@@ -39,8 +40,8 @@ export async function GET(request: NextRequest) {
 
         const where = {
             OR: [
-                { ownerId: session.user.id },
-                { members: { some: { userId: session.user.id } } },
+                { ownerId: session.user.id, owner: buildBillingAccessWhereInput() },
+                { members: { some: { userId: session.user.id } }, owner: buildBillingAccessWhereInput() },
             ],
         };
 
@@ -88,6 +89,13 @@ export async function POST(request: NextRequest) {
             return apiErrors.unauthorized();
         }
 
+        const billing = await getWorkspaceCreationEligibility(session.user.id);
+        if (!billing.canCreateWorkspace) {
+            return apiErrors.forbidden(
+                billing.reason || 'Upgrade your account to create another workspace'
+            );
+        }
+
         const body = await request.json();
         const { name, description } = body;
 
diff --git a/app/invitations/accept/page.tsx b/app/invitations/accept/page.tsx
index 8ad9119..04f99c4 100644
--- a/app/invitations/accept/page.tsx
+++ b/app/invitations/accept/page.tsx
@@ -1,5 +1,6 @@
 import { redirect } from 'next/navigation';
 import { auth } from '@/lib/auth';
+import { db } from '@/lib/db';
 import { acceptInvitationTokenForUser } from '@/lib/invitations';
 
 interface InvitationAcceptPageProps {
@@ -23,6 +24,26 @@ export default async function InvitationAcceptPage({ searchParams }: InvitationA
     redirect(`/login?callbackUrl=${encodeURIComponent(callbackUrl)}`);
   }
 
+  const invitation = await db.invitation.findUnique({
+    where: { token },
+    select: {
+      id: true,
+      status: true,
+      scope: true,
+      workspaceId: true,
+      projectId: true,
+    },
+  });
+
+  function redirectToInvitationTarget(inviteStatus: string) {
+    if (invitation?.scope === 'WORKSPACE' && invitation.workspaceId) {
+      redirect(`/workspaces/${invitation.workspaceId}?invite=${inviteStatus}`);
+    }
+    if (invitation?.scope === 'PROJECT' && invitation.projectId) {
+      redirect(`/projects/${invitation.projectId}?invite=${inviteStatus}`);
+    }
+  }
+
   const userEmail = session.user.email?.toLowerCase().trim();
   if (!userEmail) {
     redirect('/dashboard?invite=invalid_email');
@@ -35,13 +56,20 @@ export default async function InvitationAcceptPage({ searchParams }: InvitationA
   });
 
   if (result === 'accepted') {
+    redirectToInvitationTarget('accepted');
     redirect('/dashboard?invite=accepted');
   }
   if (result === 'expired') {
+    redirectToInvitationTarget('expired');
     redirect('/dashboard?invite=expired');
   }
   if (result === 'forbidden') {
     redirect('/dashboard?invite=wrong_account');
   }
+
+  if (result === 'not_found' && invitation?.status === 'ACCEPTED') {
+    redirectToInvitationTarget('already_accepted');
+  }
+
   redirect('/dashboard?invite=not_found');
 }
diff --git a/app/onboarding/onboarding-wizard.tsx b/app/onboarding/onboarding-wizard.tsx
index 7a85bf6..d82f49c 100644
--- a/app/onboarding/onboarding-wizard.tsx
+++ b/app/onboarding/onboarding-wizard.tsx
@@ -25,6 +25,13 @@ import { Card, CardContent } from '@/components/ui/card';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 import { Textarea } from '@/components/ui/textarea';
+import {
+    Select,
+    SelectContent,
+    SelectItem,
+    SelectTrigger,
+    SelectValue,
+} from '@/components/ui/select';
 import { cn } from '@/lib/utils';
 
 type Visibility = 'PRIVATE' | 'INVITE' | 'PUBLIC';
@@ -110,9 +117,17 @@ function StepWelcome({ userName, onNext }: { userName: string; onNext: () => voi
 // ─── Step 2: Create Workspace ──────────────────────────────────────────────────
 
 function StepWorkspace({
+    canCreateWorkspace,
+    availableWorkspaces,
+    selectedWorkspaceId,
+    onWorkspaceSelected,
     onNext,
     onWorkspaceCreated,
 }: {
+    canCreateWorkspace: boolean;
+    availableWorkspaces: Array<{ id: string; name: string; isOwner: boolean }>;
+    selectedWorkspaceId: string | null;
+    onWorkspaceSelected: (workspaceId: string) => void;
     onNext: () => void;
     onWorkspaceCreated: (id: string) => void;
 }) {
@@ -144,6 +159,70 @@ function StepWorkspace({
         }
     };
 
+    if (!canCreateWorkspace) {
+        return (
+            <div className="space-y-7">
+                <div className="text-center space-y-3">
+                    <div className="mx-auto w-16 h-16 rounded-full bg-primary/10 flex items-center justify-center mb-3">
+                        <Building2 className="h-8 w-8 text-primary" />
+                    </div>
+                    <h2 className="text-2xl font-bold tracking-tight">Workspace access</h2>
+                    <p className="text-base text-muted-foreground">
+                        Your account can&apos;t create a new workspace right now.
+                    </p>
+                </div>
+
+                {availableWorkspaces.length > 0 ? (
+                    <div className="space-y-5">
+                        <div className="flex items-start gap-3 rounded-lg border border-dashed p-4 text-sm text-muted-foreground">
+                            <Info className="h-4 w-4 shrink-0 mt-0.5" />
+                            <span>
+                                You can still create projects inside workspaces where you already have admin access.
+                            </span>
+                        </div>
+
+                        <div className="space-y-2">
+                            <Label htmlFor="onboarding-workspace">Choose a workspace</Label>
+                            <Select
+                                value={selectedWorkspaceId ?? undefined}
+                                onValueChange={onWorkspaceSelected}
+                            >
+                                <SelectTrigger id="onboarding-workspace" className="w-full">
+                                    <SelectValue placeholder="Select a workspace" />
+                                </SelectTrigger>
+                                <SelectContent>
+                                    {availableWorkspaces.map((workspace) => (
+                                        <SelectItem key={workspace.id} value={workspace.id}>
+                                            {workspace.name}{workspace.isOwner ? ' (Owner)' : ' (Admin)'}
+                                        </SelectItem>
+                                    ))}
+                                </SelectContent>
+                            </Select>
+                        </div>
+
+                        <Button onClick={onNext} className="w-full h-11" disabled={!selectedWorkspaceId}>
+                            Continue
+                            <ChevronRight className="h-4 w-4 ml-1" />
+                        </Button>
+                    </div>
+                ) : (
+                    <div className="space-y-4">
+                        <div className="flex items-start gap-3 rounded-lg border border-dashed p-4 text-sm text-muted-foreground">
+                            <Info className="h-4 w-4 shrink-0 mt-0.5" />
+                            <span>
+                                You don&apos;t currently have a workspace where you can create projects. Ask a workspace owner to invite you as an admin, or upgrade later to create your own workspace.
+                            </span>
+                        </div>
+                        <Button onClick={onNext} className="w-full h-11">
+                            Continue
+                            <ChevronRight className="h-4 w-4 ml-1" />
+                        </Button>
+                    </div>
+                )}
+            </div>
+        );
+    }
+
     return (
         <div className="space-y-7">
             <div className="text-center space-y-3">
@@ -217,10 +296,14 @@ function StepWorkspace({
 
 function StepProject({
     workspaceId,
+    availableWorkspaces,
+    canCreateWorkspace,
     onNext,
     onProjectCreated,
 }: {
     workspaceId: string | null;
+    availableWorkspaces: Array<{ id: string; name: string; isOwner: boolean }>;
+    canCreateWorkspace: boolean;
     onNext: () => void;
     onProjectCreated: (id: string) => void;
 }) {
@@ -273,7 +356,13 @@ function StepProject({
                 <div className="space-y-4">
                     <div className="flex items-start gap-3 rounded-lg border border-dashed p-4 text-sm text-muted-foreground">
                         <Info className="h-4 w-4 shrink-0 mt-0.5" />
-                        <span>You skipped workspace creation. Projects require a workspace — you can create both from the dashboard later.</span>
+                        <span>
+                            {canCreateWorkspace
+                                ? 'You skipped workspace creation. Projects require a workspace — you can create both from the dashboard later.'
+                                : availableWorkspaces.length === 0
+                                    ? 'You do not currently have permission to create projects in any workspace.'
+                                    : 'Pick a workspace in the previous step to create a project here.'}
+                        </span>
                     </div>
                     <Button onClick={onNext} className="w-full h-11">
                         Continue
@@ -547,10 +636,18 @@ function StepNotifications({ onFinish }: { onFinish: () => Promise<void> }) {
 
 // ─── Wizard Shell ──────────────────────────────────────────────────────────────
 
-export function OnboardingWizard({ userName }: { userName: string }) {
+export function OnboardingWizard({
+    userName,
+    canCreateWorkspace,
+    availableWorkspaces,
+}: {
+    userName: string;
+    canCreateWorkspace: boolean;
+    availableWorkspaces: Array<{ id: string; name: string; isOwner: boolean }>;
+}) {
     const router = useRouter();
     const [currentStep, setCurrentStep] = useState(1);
-    const [createdWorkspaceId, setCreatedWorkspaceId] = useState<string | null>(null);
+    const [createdWorkspaceId, setCreatedWorkspaceId] = useState<string | null>(availableWorkspaces[0]?.id ?? null);
     const [isCompleting, setIsCompleting] = useState(false);
 
     const goNext = () => setCurrentStep((s) => Math.min(s + 1, TOTAL_STEPS));
@@ -615,10 +712,23 @@ export function OnboardingWizard({ userName }: { userName: string }) {
                         <StepWelcome userName={userName} onNext={goNext} />
                     )}
                     {currentStep === 2 && (
-                        <StepWorkspace onNext={goNext} onWorkspaceCreated={setCreatedWorkspaceId} />
+                        <StepWorkspace
+                            canCreateWorkspace={canCreateWorkspace}
+                            availableWorkspaces={availableWorkspaces}
+                            selectedWorkspaceId={createdWorkspaceId}
+                            onWorkspaceSelected={setCreatedWorkspaceId}
+                            onNext={goNext}
+                            onWorkspaceCreated={setCreatedWorkspaceId}
+                        />
                     )}
                     {currentStep === 3 && (
-                        <StepProject workspaceId={createdWorkspaceId} onNext={goNext} onProjectCreated={() => {}} />
+                        <StepProject
+                            workspaceId={createdWorkspaceId}
+                            availableWorkspaces={availableWorkspaces}
+                            canCreateWorkspace={canCreateWorkspace}
+                            onNext={goNext}
+                            onProjectCreated={() => {}}
+                        />
                     )}
                     {currentStep === 4 && (
                         <StepVideo onNext={goNext} />
diff --git a/app/onboarding/page.tsx b/app/onboarding/page.tsx
index 6082449..082fcf1 100644
--- a/app/onboarding/page.tsx
+++ b/app/onboarding/page.tsx
@@ -1,4 +1,5 @@
 import { auth } from '@/lib/auth';
+import { buildBillingAccessWhereInput, getBillingOverview } from '@/lib/billing';
 import { db } from '@/lib/db';
 import { redirect } from 'next/navigation';
 import { OnboardingWizard } from './onboarding-wizard';
@@ -9,10 +10,28 @@ export default async function OnboardingPage() {
         redirect('/login');
     }
 
-    const user = await db.user.findUnique({
-        where: { id: session.user.id },
-        select: { onboardingCompletedAt: true, name: true, email: true },
-    });
+    const [user, billing, creatableWorkspaces] = await Promise.all([
+        db.user.findUnique({
+            where: { id: session.user.id },
+            select: { onboardingCompletedAt: true, name: true, email: true },
+        }),
+        getBillingOverview(session.user.id),
+        db.workspace.findMany({
+            where: {
+                owner: buildBillingAccessWhereInput(),
+                OR: [
+                    { ownerId: session.user.id },
+                    { members: { some: { userId: session.user.id, role: 'ADMIN' } } },
+                ],
+            },
+            select: {
+                id: true,
+                name: true,
+                ownerId: true,
+            },
+            orderBy: { name: 'asc' },
+        }),
+    ]);
 
     if (user?.onboardingCompletedAt) {
         redirect('/dashboard');
@@ -20,5 +39,15 @@ export default async function OnboardingPage() {
 
     const userName = user?.name || user?.email?.split('@')[0] || 'there';
 
-    return <OnboardingWizard userName={userName} />;
+    return (
+        <OnboardingWizard
+            userName={userName}
+            canCreateWorkspace={billing.workspaceCreation.canCreateWorkspace}
+            availableWorkspaces={creatableWorkspaces.map((workspace) => ({
+                id: workspace.id,
+                name: workspace.name,
+                isOwner: workspace.ownerId === session.user.id,
+            }))}
+        />
+    );
 }
diff --git a/bun.lock b/bun.lock
index 0961233..6f6b6e0 100644
--- a/bun.lock
+++ b/bun.lock
@@ -27,6 +27,7 @@
         "react-window": "^2.2.7",
         "sharp": "^0.34.5",
         "sonner": "^2.0.7",
+        "stripe": "^20.4.1",
         "tailwind-merge": "^3.4.0",
         "tus-js-client": "^4.3.1",
         "tw-animate-css": "^1.4.0",
@@ -1732,6 +1733,8 @@
 
     "strip-json-comments": ["strip-json-comments@3.1.1", "", {}, "sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig=="],
 
+    "stripe": ["stripe@20.4.1", "", { "peerDependencies": { "@types/node": ">=16" }, "optionalPeers": ["@types/node"] }, "sha512-axCguHItc8Sxt0HC6aSkdVRPffjYPV7EQqZRb2GkIa8FzWDycE7nHJM19C6xAIynH1Qp1/BHiopSi96jGBxT0w=="],
+
     "strnum": ["strnum@2.1.2", "", {}, "sha512-l63NF9y/cLROq/yqKXSLtcMeeyOfnSQlfMSlzFt/K73oIaD8DGaQWd7Z34X9GPiKqP5rbSh84Hl4bOlLcjiSrQ=="],
 
     "styled-jsx": ["styled-jsx@5.1.6", "", { "dependencies": { "client-only": "0.0.1" }, "peerDependencies": { "react": ">= 16.8.0 || 17.x.x || ^18.0.0-0 || ^19.0.0-0" } }, "sha512-qSVyDTeMotdvQYoHWLNGwRFJHC+i+ZvdBRYosOFgC+Wg1vx4frN2/RG/NA7SYqqvKNLf39P2LSRA2pu6n0XYZA=="],
diff --git a/components/layout/header.tsx b/components/layout/header.tsx
index c5dcc18..4b4c641 100644
--- a/components/layout/header.tsx
+++ b/components/layout/header.tsx
@@ -59,9 +59,10 @@ interface HeaderProps {
     image?: string | null;
     isAdmin?: boolean;
   } | null;
+  showAppNavigation?: boolean;
 }
 
-export function Header({ user }: HeaderProps) {
+export function Header({ user, showAppNavigation = false }: HeaderProps) {
   const pathname = usePathname();
   const [shortcutsOpen, setShortcutsOpen] = useState(false);
   const [searchOpen, setSearchOpen] = useState(false);
@@ -70,13 +71,17 @@ export function Header({ user }: HeaderProps) {
   useEffect(() => {
     const handler = (e: KeyboardEvent) => {
       if ((e.ctrlKey || e.metaKey) && e.key === 'k') {
+        if (!user || !showAppNavigation) {
+          return;
+        }
+
         e.preventDefault();
-        if (user) setSearchOpen((v) => !v);
+        setSearchOpen((v) => !v);
       }
     };
     window.addEventListener('keydown', handler);
     return () => window.removeEventListener('keydown', handler);
-  }, [user]);
+  }, [showAppNavigation, user]);
 
   // Hide header on video player pages — they use full viewport with their own back button
   const isVideoPage = /\/videos\/[^/]+($|\/compare)/.test(pathname) || pathname.startsWith('/watch/');
@@ -97,7 +102,7 @@ export function Header({ user }: HeaderProps) {
             <SheetTitle className="sr-only">Navigation Menu</SheetTitle>
             <SheetDescription className="sr-only">Access your projects and workspaces</SheetDescription>
             <nav className="flex flex-col gap-2 mt-10">
-              {navItems.map((item) => (
+              {showAppNavigation && navItems.map((item) => (
                 <Link
                   key={item.href}
                   href={item.href}
@@ -138,7 +143,7 @@ export function Header({ user }: HeaderProps) {
 
         {/* Desktop nav */}
         <nav className="hidden md:flex items-center gap-1">
-          {navItems.map((item) => (
+          {showAppNavigation && navItems.map((item) => (
             <Link
               key={item.href}
               href={item.href}
@@ -171,7 +176,7 @@ export function Header({ user }: HeaderProps) {
 
         {/* Right side */}
         <div className="flex items-center gap-2 ml-auto">
-          {user && (
+          {user && showAppNavigation && (
             <TooltipProvider>
               <Tooltip>
                 <TooltipTrigger asChild>
@@ -193,7 +198,7 @@ export function Header({ user }: HeaderProps) {
               </Tooltip>
             </TooltipProvider>
           )}
-          {user && (
+          {user && showAppNavigation && (
             <Button asChild variant="outline" size="sm" className="hidden sm:inline-flex">
               <Link href="/feedback">
                 <MessageSquareQuote className="h-4 w-4 mr-1.5" />
@@ -201,7 +206,7 @@ export function Header({ user }: HeaderProps) {
               </Link>
             </Button>
           )}
-          {user && (
+          {user && showAppNavigation && (
             <Button asChild variant="ghost" size="icon" className="sm:hidden" aria-label="Feedback and reviews">
               <Link href="/feedback">
                 <MessageSquareQuote className="h-4 w-4" />
@@ -223,12 +228,16 @@ export function Header({ user }: HeaderProps) {
                   </Avatar>
                 </Button>
               </DropdownMenuTrigger>
-              <DropdownMenuContent align="end" className="w-56">
-                <div className="flex items-center justify-start gap-2 p-2">
+              <DropdownMenuContent
+                align="end"
+                sideOffset={10}
+                className="w-64 min-w-64 rounded-md border bg-popover/98 p-1 shadow-2xl backdrop-blur-md"
+              >
+                <div className="rounded-sm px-3 py-2.5">
                   <div className="flex flex-col space-y-1 leading-none">
                     {user.name && <p className="font-medium">{user.name}</p>}
                     {user.email && (
-                      <p className="w-[200px] truncate text-sm text-muted-foreground">
+                      <p className="truncate text-sm text-muted-foreground">
                         {user.email}
                       </p>
                     )}
@@ -273,7 +282,7 @@ export function Header({ user }: HeaderProps) {
         </div>
       </div>
       <KeyboardShortcutsModal open={shortcutsOpen} onOpenChange={setShortcutsOpen} />
-      {user && <SearchModal open={searchOpen} onOpenChange={setSearchOpen} />}
+      {user && showAppNavigation && <SearchModal open={searchOpen} onOpenChange={setSearchOpen} />}
     </header>
   );
 }
diff --git a/lib/auth.ts b/lib/auth.ts
index 9eb1bf7..508530a 100644
--- a/lib/auth.ts
+++ b/lib/auth.ts
@@ -3,6 +3,7 @@ import Credentials from 'next-auth/providers/credentials';
 import bcrypt from 'bcryptjs';
 import { db } from '@/lib/db';
 import { ProjectMemberRole, WorkspaceMemberRole } from '@prisma/client';
+import { hasBillingAccess } from '@/lib/billing';
 
 // Dummy hash for timing-safe comparison when user doesn't exist
 // This prevents user enumeration via timing attacks
@@ -114,6 +115,7 @@ export async function checkProjectAccess(
 
   // Check workspace membership/role
   let workspaceRole: WorkspaceMemberRole | 'OWNER' | null = null;
+  let workspaceOwnerBillingAccess = false;
   if (shouldLoadWorkspaceRole && userId) {
     const [wsMember, wsOwner] = await Promise.all([
       db.workspaceMember.findUnique({
@@ -121,7 +123,17 @@ export async function checkProjectAccess(
       }),
       db.workspace.findUnique({
         where: { id: project.workspaceId },
-        select: { ownerId: true },
+        select: {
+          ownerId: true,
+          owner: {
+            select: {
+              subscriptionStatus: true,
+              trialEndsAt: true,
+              stripeCurrentPeriodEnd: true,
+              billingAccessEndedAt: true,
+            },
+          },
+        },
       }),
     ]);
 
@@ -130,13 +142,32 @@ export async function checkProjectAccess(
     } else if (wsMember) {
       workspaceRole = wsMember.role;
     }
+
+    if (wsOwner?.owner) {
+      workspaceOwnerBillingAccess = hasBillingAccess(wsOwner.owner);
+    }
+  } else {
+    const wsOwner = await db.workspace.findUnique({
+      where: { id: project.workspaceId },
+      select: {
+        owner: {
+          select: {
+            subscriptionStatus: true,
+            trialEndsAt: true,
+            stripeCurrentPeriodEnd: true,
+            billingAccessEndedAt: true,
+          },
+        },
+      },
+    });
+    workspaceOwnerBillingAccess = wsOwner?.owner ? hasBillingAccess(wsOwner.owner) : false;
   }
   const isWorkspaceMember = !!workspaceRole;
   const isWorkspaceAdmin = workspaceRole === WorkspaceMemberRole.ADMIN || workspaceRole === 'OWNER';
 
-  const hasAccess = isOwner || isProjectMember || isPublic || isWorkspaceMember;
-  const canEdit = isOwner || isProjectAdmin || isWorkspaceAdmin;
-  const canDelete = isOwner || workspaceRole === 'OWNER';
+  const hasAccess = workspaceOwnerBillingAccess && (isOwner || isProjectMember || isPublic || isWorkspaceMember);
+  const canEdit = workspaceOwnerBillingAccess && (isOwner || isProjectAdmin || isWorkspaceAdmin);
+  const canDelete = workspaceOwnerBillingAccess && (isOwner || workspaceRole === 'OWNER');
 
   return {
     isOwner,
@@ -147,6 +178,7 @@ export async function checkProjectAccess(
     hasAccess,
     canEdit,
     canDelete,
+    ownerBillingActive: workspaceOwnerBillingAccess,
   };
 }
 
@@ -166,9 +198,20 @@ export async function checkWorkspaceAccess(
   const isMember = !!workspaceMember;
   const isAdmin = workspaceMember?.role === WorkspaceMemberRole.ADMIN;
 
-  const hasAccess = isOwner || isMember;
-  const canEdit = isOwner || isAdmin;
-  const canDelete = isOwner;
+  const owner = await db.user.findUnique({
+    where: { id: workspace.ownerId },
+    select: {
+      subscriptionStatus: true,
+      trialEndsAt: true,
+      stripeCurrentPeriodEnd: true,
+      billingAccessEndedAt: true,
+    },
+  });
+  const ownerBillingActive = owner ? hasBillingAccess(owner) : false;
+
+  const hasAccess = ownerBillingActive && (isOwner || isMember);
+  const canEdit = ownerBillingActive && (isOwner || isAdmin);
+  const canDelete = ownerBillingActive && isOwner;
 
   return {
     isOwner,
@@ -177,5 +220,6 @@ export async function checkWorkspaceAccess(
     hasAccess,
     canEdit,
     canDelete,
+    ownerBillingActive,
   };
 }
diff --git a/lib/billing.ts b/lib/billing.ts
new file mode 100644
index 0000000..d02a4db
--- /dev/null
+++ b/lib/billing.ts
@@ -0,0 +1,418 @@
+import type { Prisma } from '@prisma/client';
+import type Stripe from 'stripe';
+import { BillingSubscriptionStatus } from '@prisma/client';
+import { db } from '@/lib/db';
+import { getStripe, getStripePriceId } from '@/lib/stripe';
+
+const ACTIVE_SUBSCRIPTION_STATUSES = new Set<BillingSubscriptionStatus>([
+  BillingSubscriptionStatus.ACTIVE,
+  BillingSubscriptionStatus.TRIALING,
+]);
+
+export const DEFAULT_TRIAL_PERIOD_DAYS = 7;
+const STORAGE_CLEANUP_GRACE_DAYS = 15;
+
+type BillingAccessSubject = {
+  subscriptionStatus: BillingSubscriptionStatus;
+  trialEndsAt: Date | null;
+  stripeCurrentPeriodEnd: Date | null;
+  stripeCancelAtPeriodEnd?: boolean | null;
+  stripeCancelAt?: Date | null;
+  billingAccessEndedAt: Date | null;
+};
+
+export function getDefaultTrialEndsAt(from: Date = new Date()) {
+  return new Date(from.getTime() + DEFAULT_TRIAL_PERIOD_DAYS * 24 * 60 * 60 * 1000);
+}
+
+export function hasActiveTrial(trialEndsAt: Date | null | undefined, now: Date = new Date()) {
+  return Boolean(trialEndsAt && trialEndsAt.getTime() > now.getTime());
+}
+
+export function hasActiveSubscription(status: BillingSubscriptionStatus | null | undefined) {
+  if (!status) return false;
+  return ACTIVE_SUBSCRIPTION_STATUSES.has(status);
+}
+
+export function hasBillingAccess(subject: BillingAccessSubject, now: Date = new Date()) {
+  if (hasActiveSubscription(subject.subscriptionStatus)) {
+    return true;
+  }
+
+  if (hasActiveTrial(subject.trialEndsAt, now)) {
+    return true;
+  }
+
+  return Boolean(
+    subject.stripeCurrentPeriodEnd && subject.stripeCurrentPeriodEnd.getTime() > now.getTime()
+  );
+}
+
+export function getBillingAccessEndDate(subject: BillingAccessSubject) {
+  if (subject.billingAccessEndedAt) {
+    return subject.billingAccessEndedAt;
+  }
+
+  if (subject.stripeCurrentPeriodEnd) {
+    return subject.stripeCurrentPeriodEnd;
+  }
+
+  return subject.trialEndsAt;
+}
+
+export function getStorageCleanupEligibleAt(subject: BillingAccessSubject) {
+  const accessEndDate = getBillingAccessEndDate(subject);
+  if (!accessEndDate) return null;
+
+  return new Date(accessEndDate.getTime() + STORAGE_CLEANUP_GRACE_DAYS * 24 * 60 * 60 * 1000);
+}
+
+export function buildBillingAccessWhereInput(now: Date = new Date()): Prisma.UserWhereInput {
+  return {
+    OR: [
+      { subscriptionStatus: { in: [BillingSubscriptionStatus.ACTIVE, BillingSubscriptionStatus.TRIALING] } },
+      { trialEndsAt: { gt: now } },
+      { stripeCurrentPeriodEnd: { gt: now } },
+    ],
+  };
+}
+
+export function buildExpiredBillingWhereInput(now: Date = new Date()): Prisma.UserWhereInput {
+  const cleanupCutoff = new Date(now.getTime() - STORAGE_CLEANUP_GRACE_DAYS * 24 * 60 * 60 * 1000);
+
+  return {
+    AND: [
+      {
+        NOT: buildBillingAccessWhereInput(now),
+      },
+      {
+        OR: [
+          { billingAccessEndedAt: { lte: cleanupCutoff } },
+          {
+            AND: [
+              { billingAccessEndedAt: null },
+              { trialEndsAt: { lte: cleanupCutoff } },
+            ],
+          },
+        ],
+      },
+    ],
+  };
+}
+
+export function mapStripeSubscriptionStatus(
+  status: Stripe.Subscription.Status | null | undefined
+): BillingSubscriptionStatus {
+  switch (status) {
+    case 'trialing':
+      return BillingSubscriptionStatus.TRIALING;
+    case 'active':
+      return BillingSubscriptionStatus.ACTIVE;
+    case 'past_due':
+      return BillingSubscriptionStatus.PAST_DUE;
+    case 'canceled':
+      return BillingSubscriptionStatus.CANCELED;
+    case 'unpaid':
+      return BillingSubscriptionStatus.UNPAID;
+    case 'incomplete':
+      return BillingSubscriptionStatus.INCOMPLETE;
+    case 'incomplete_expired':
+      return BillingSubscriptionStatus.INCOMPLETE_EXPIRED;
+    default:
+      return BillingSubscriptionStatus.FREE;
+  }
+}
+
+export function getBillingStatusLabel(status: BillingSubscriptionStatus) {
+  switch (status) {
+    case BillingSubscriptionStatus.TRIALING:
+      return 'Trialing';
+    case BillingSubscriptionStatus.ACTIVE:
+      return 'Active';
+    case BillingSubscriptionStatus.PAST_DUE:
+      return 'Past due';
+    case BillingSubscriptionStatus.CANCELED:
+      return 'Canceled';
+    case BillingSubscriptionStatus.UNPAID:
+      return 'Unpaid';
+    case BillingSubscriptionStatus.INCOMPLETE:
+      return 'Incomplete';
+    case BillingSubscriptionStatus.INCOMPLETE_EXPIRED:
+      return 'Expired';
+    case BillingSubscriptionStatus.FREE:
+    default:
+      return 'Free';
+  }
+}
+
+export async function getStripeCheckoutState(userId: string) {
+  const user = await db.user.findUnique({
+    where: { id: userId },
+    select: {
+      subscriptionStatus: true,
+      billingTrialConsumedAt: true,
+    },
+  });
+
+  if (!user) {
+    throw new Error(`User ${userId} not found`);
+  }
+
+  return {
+    hasActiveSubscription: hasActiveSubscription(user.subscriptionStatus),
+    isTrialEligible: !user.billingTrialConsumedAt,
+  };
+}
+
+export async function getWorkspaceCreationEligibility(userId: string) {
+  const [user, ownedWorkspaceCount, invitedWorkspaceCount, projectOnlyCollaborationCount] = await Promise.all([
+    db.user.findUnique({
+      where: { id: userId },
+      select: {
+        subscriptionStatus: true,
+        trialEndsAt: true,
+        stripeCustomerId: true,
+        stripeSubscriptionId: true,
+        stripePriceId: true,
+        stripeCurrentPeriodEnd: true,
+        stripeCancelAtPeriodEnd: true,
+        stripeCancelAt: true,
+        billingAccessEndedAt: true,
+      },
+    }),
+    db.workspace.count({
+      where: { ownerId: userId },
+    }),
+    db.workspaceMember.count({
+      where: {
+        userId,
+        workspace: {
+          ownerId: {
+            not: userId,
+          },
+        },
+      },
+    }),
+    db.projectMember.count({
+      where: {
+        userId,
+        project: {
+          ownerId: {
+            not: userId,
+          },
+          workspace: {
+            ownerId: {
+              not: userId,
+            },
+          },
+        },
+      },
+    }),
+  ]);
+
+  if (!user) {
+    throw new Error(`User ${userId} not found`);
+  }
+
+  const billingAccess = hasBillingAccess(user);
+  const collaborationCount = invitedWorkspaceCount + projectOnlyCollaborationCount;
+  const canCreateWorkspace =
+    billingAccess || (ownedWorkspaceCount === 0 && collaborationCount === 0);
+
+  let reason: string | null = null;
+  if (!canCreateWorkspace) {
+    if (collaborationCount > 0 && ownedWorkspaceCount === 0) {
+      reason =
+        'You are currently collaborating in someone else’s workspace or project. Start a subscription to create a workspace of your own.';
+    } else {
+      reason =
+        'Your trial has ended. Start a subscription to create and keep owning workspaces.';
+    }
+  }
+
+  return {
+    canCreateWorkspace,
+    reason,
+    ownedWorkspaceCount,
+    invitedWorkspaceCount,
+    projectOnlyCollaborationCount,
+    subscription: {
+      status: user.subscriptionStatus,
+      label: getBillingStatusLabel(user.subscriptionStatus),
+      hasActiveSubscription: hasActiveSubscription(user.subscriptionStatus),
+      hasActiveTrial: hasActiveTrial(user.trialEndsAt),
+      hasBillingAccess: billingAccess,
+      stripeCustomerId: user.stripeCustomerId,
+      stripeSubscriptionId: user.stripeSubscriptionId,
+      stripePriceId: user.stripePriceId,
+      currentPeriodEnd: user.stripeCurrentPeriodEnd,
+      cancelAtPeriodEnd: user.stripeCancelAtPeriodEnd,
+      cancelAt: user.stripeCancelAt,
+      trialEndsAt: user.trialEndsAt,
+      billingAccessEndedAt: user.billingAccessEndedAt,
+      storageCleanupEligibleAt: getStorageCleanupEligibleAt(user),
+    },
+  };
+}
+
+export async function getBillingOverview(userId: string) {
+  const billing = await getWorkspaceCreationEligibility(userId);
+
+  return {
+    workspaceCreation: {
+      canCreateWorkspace: billing.canCreateWorkspace,
+      reason: billing.reason,
+      ownedWorkspaceCount: billing.ownedWorkspaceCount,
+      invitedWorkspaceCount: billing.invitedWorkspaceCount,
+    },
+    subscription: billing.subscription,
+  };
+}
+
+export async function getOrCreateStripeCustomerId(userId: string) {
+  const user = await db.user.findUnique({
+    where: { id: userId },
+    select: {
+      id: true,
+      email: true,
+      name: true,
+      stripeCustomerId: true,
+    },
+  });
+
+  if (!user) {
+    throw new Error(`User ${userId} not found`);
+  }
+
+  if (user.stripeCustomerId) {
+    return user.stripeCustomerId;
+  }
+
+  const stripe = getStripe();
+  const customer = await stripe.customers.create({
+    email: user.email ?? undefined,
+    name: user.name ?? undefined,
+    metadata: { userId: user.id },
+  });
+
+  await db.user.update({
+    where: { id: user.id },
+    data: { stripeCustomerId: customer.id },
+  });
+
+  return customer.id;
+}
+
+function getStripeTimestamp(value: unknown): number | null {
+  return typeof value === 'number' ? value : null;
+}
+
+function getInactiveBillingAccessEndedAt(subscription: Stripe.Subscription, currentPeriodEnd: number | null) {
+  const endedAt = getStripeTimestamp((subscription as Stripe.Subscription & { ended_at?: unknown }).ended_at);
+  const canceledAt = getStripeTimestamp((subscription as Stripe.Subscription & { canceled_at?: unknown }).canceled_at);
+  const reference = currentPeriodEnd ?? endedAt ?? canceledAt;
+
+  return reference ? new Date(reference * 1000) : new Date();
+}
+
+function getEntitledStripePriceId(subscription: Stripe.Subscription) {
+  const configuredPriceId = getStripePriceId();
+
+  return subscription.items.data.find((item) => item.price.id === configuredPriceId)?.price.id ?? null;
+}
+
+export async function syncStripeSubscriptionToUser(subscription: Stripe.Subscription) {
+  const customerId =
+    typeof subscription.customer === 'string'
+      ? subscription.customer
+      : subscription.customer.id;
+
+  const user = await db.user.findUnique({
+    where: { stripeCustomerId: customerId },
+    select: {
+      id: true,
+      billingTrialConsumedAt: true,
+    },
+  });
+
+  if (!user) {
+    return null;
+  }
+
+  const currentPeriodEnd =
+    'current_period_end' in subscription && typeof subscription.current_period_end === 'number'
+      ? subscription.current_period_end
+      : null;
+  const cancelAt =
+    'cancel_at' in subscription && typeof subscription.cancel_at === 'number'
+      ? subscription.cancel_at
+      : null;
+  const cancelAtPeriodEnd =
+    'cancel_at_period_end' in subscription && typeof subscription.cancel_at_period_end === 'boolean'
+      ? subscription.cancel_at_period_end
+      : false;
+  const trialEnd =
+    'trial_end' in subscription && typeof subscription.trial_end === 'number'
+      ? subscription.trial_end
+      : null;
+  const entitledPriceId = getEntitledStripePriceId(subscription);
+  const hasEntitledPrice = Boolean(entitledPriceId);
+  const mappedStatus = hasEntitledPrice
+    ? mapStripeSubscriptionStatus(subscription.status)
+    : BillingSubscriptionStatus.FREE;
+  const effectiveCurrentPeriodEnd = hasEntitledPrice && currentPeriodEnd
+    ? new Date(currentPeriodEnd * 1000)
+    : null;
+  const effectiveTrialEnd = hasEntitledPrice && trialEnd
+    ? new Date(trialEnd * 1000)
+    : null;
+  const hasAccess = hasEntitledPrice
+    && (hasActiveSubscription(mappedStatus) || Boolean(currentPeriodEnd && currentPeriodEnd * 1000 > Date.now()));
+
+  return db.user.update({
+    where: { id: user.id },
+    data: {
+      stripeSubscriptionId: subscription.id,
+      stripePriceId: entitledPriceId ?? subscription.items.data[0]?.price.id ?? null,
+      stripeCurrentPeriodEnd: effectiveCurrentPeriodEnd,
+      stripeCancelAtPeriodEnd: cancelAtPeriodEnd,
+      stripeCancelAt: cancelAt ? new Date(cancelAt * 1000) : null,
+      subscriptionStatus: mappedStatus,
+      trialEndsAt: effectiveTrialEnd,
+      billingTrialConsumedAt: hasEntitledPrice && trialEnd
+        ? (user.billingTrialConsumedAt ?? new Date())
+        : user.billingTrialConsumedAt,
+      billingAccessEndedAt: hasAccess
+        ? null
+        : getInactiveBillingAccessEndedAt(subscription, hasEntitledPrice ? currentPeriodEnd : null),
+    },
+  });
+}
+
+export async function markSubscriptionCanceledByCustomerId(
+  customerId: string,
+  options?: { currentPeriodEnd?: Date | null; endedAt?: Date | null }
+) {
+  const user = await db.user.findUnique({
+    where: { stripeCustomerId: customerId },
+    select: { id: true },
+  });
+
+  if (!user) {
+    return null;
+  }
+
+  return db.user.update({
+    where: { id: user.id },
+    data: {
+      subscriptionStatus: BillingSubscriptionStatus.CANCELED,
+      trialEndsAt: null,
+      stripeSubscriptionId: null,
+      stripePriceId: null,
+      stripeCurrentPeriodEnd: options?.currentPeriodEnd ?? null,
+      stripeCancelAtPeriodEnd: false,
+      stripeCancelAt: null,
+      billingAccessEndedAt: options?.endedAt ?? options?.currentPeriodEnd ?? new Date(),
+    },
+  });
+}
diff --git a/lib/route-access.ts b/lib/route-access.ts
index a3c2f79..2b7eed4 100644
--- a/lib/route-access.ts
+++ b/lib/route-access.ts
@@ -1,11 +1,13 @@
 import { notFound, redirect } from 'next/navigation';
 import { auth, checkProjectAccess, checkWorkspaceAccess } from '@/lib/auth';
+import { hasBillingAccess } from '@/lib/billing';
 import { db } from '@/lib/db';
 
 type AccessIntent = 'view' | 'manage';
 
 const LOGIN_REDIRECT = '/login';
 const FORBIDDEN_REDIRECT = '/dashboard';
+const BILLING_REDIRECT = '/settings';
 
 function redirectForMissingAuth() {
   redirect(LOGIN_REDIRECT);
@@ -15,6 +17,10 @@ function redirectForForbidden() {
   redirect(FORBIDDEN_REDIRECT);
 }
 
+function redirectForBilling() {
+  redirect(BILLING_REDIRECT);
+}
+
 function ensureGuestPolicy(options: { userId?: string; intent: AccessIntent; allowPublicView: boolean }) {
   const { userId, intent, allowPublicView } = options;
   if (userId) return;
@@ -60,6 +66,92 @@ export async function requireAuthOrRedirect() {
   return session;
 }
 
+export async function requireBillingAccessOrRedirect(options?: {
+  userId?: string;
+}) {
+  const resolvedUserId = options?.userId ?? (await auth())?.user?.id;
+
+  if (!resolvedUserId) {
+    redirectForMissingAuth();
+  }
+
+  const user = await db.user.findUnique({
+    where: { id: resolvedUserId },
+    select: {
+      subscriptionStatus: true,
+      trialEndsAt: true,
+      stripeCurrentPeriodEnd: true,
+      billingAccessEndedAt: true,
+    },
+  });
+
+  if (!user || !hasBillingAccess(user)) {
+    redirectForBilling();
+  }
+
+  return user;
+}
+
+export async function hasCollaboratorBillingBackedAccess(userId: string) {
+  const now = new Date();
+
+  const [workspaceCount, projectCount] = await Promise.all([
+    db.workspace.count({
+      where: {
+        owner: {
+          OR: [
+            { subscriptionStatus: { in: ['ACTIVE', 'TRIALING'] } },
+            { trialEndsAt: { gt: now } },
+            { stripeCurrentPeriodEnd: { gt: now } },
+          ],
+        },
+        OR: [
+          { ownerId: userId },
+          { members: { some: { userId } } },
+        ],
+      },
+    }),
+    db.project.count({
+      where: {
+        workspace: {
+          owner: {
+            OR: [
+              { subscriptionStatus: { in: ['ACTIVE', 'TRIALING'] } },
+              { trialEndsAt: { gt: now } },
+              { stripeCurrentPeriodEnd: { gt: now } },
+            ],
+          },
+        },
+        OR: [
+          { ownerId: userId },
+          { members: { some: { userId } } },
+          { workspace: { members: { some: { userId } } } },
+        ],
+      },
+    }),
+  ]);
+
+  return workspaceCount > 0 || projectCount > 0;
+}
+
+export async function hasAppNavigationAccess(userId: string) {
+  const user = await db.user.findUnique({
+    where: { id: userId },
+    select: {
+      subscriptionStatus: true,
+      trialEndsAt: true,
+      stripeCurrentPeriodEnd: true,
+      billingAccessEndedAt: true,
+    },
+  });
+
+  if (user && hasBillingAccess(user)) {
+    return true;
+  }
+
+  return hasCollaboratorBillingBackedAccess(userId);
+}
+
 export async function requireWorkspaceAccessOrRedirect(options: {
   workspaceId: string;
   userId?: string;
@@ -84,10 +176,16 @@ export async function requireWorkspaceAccessOrRedirect(options: {
   const access = await checkWorkspaceAccess(workspace, resolvedUserId);
 
   if (!access.hasAccess) {
+    if (!access.ownerBillingActive) {
+      redirectForBilling();
+    }
     redirectForForbidden();
   }
 
   if (intent === 'manage' && !access.canEdit) {
+    if (!access.ownerBillingActive) {
+      redirectForBilling();
+    }
     redirectForForbidden();
   }
 
diff --git a/lib/share-links.ts b/lib/share-links.ts
index 4c42bc7..1aef3c2 100644
--- a/lib/share-links.ts
+++ b/lib/share-links.ts
@@ -1,6 +1,7 @@
 import bcrypt from 'bcryptjs';
 import type { ShareLink, SharePermission } from '@prisma/client';
 import { db } from '@/lib/db';
+import { hasBillingAccess } from '@/lib/billing';
 
 export const MAX_SHARE_PASSWORD_LENGTH = 128;
 
@@ -45,6 +46,24 @@ export async function validateShareLinkAccess({
 }: ValidateShareLinkParams): Promise<ShareLinkAccessResult> {
   const link = await db.shareLink.findUnique({
     where: { token },
+    include: {
+      project: {
+        select: {
+          workspace: {
+            select: {
+              owner: {
+                select: {
+                  subscriptionStatus: true,
+                  trialEndsAt: true,
+                  stripeCurrentPeriodEnd: true,
+                  billingAccessEndedAt: true,
+                },
+              },
+            },
+          },
+        },
+      },
+    },
   });
 
   if (!link) {
@@ -60,6 +79,10 @@ export async function validateShareLinkAccess({
     return { hasAccess: false, canComment: false, canDownload: false, allowGuests: false, requiresPassword: false, link };
   }
 
+  if (!link.project?.workspace.owner || !hasBillingAccess(link.project.workspace.owner)) {
+    return { hasAccess: false, canComment: false, canDownload: false, allowGuests: false, requiresPassword: false, link };
+  }
+
   if (link.passwordHash && !passwordVerified) {
     if (!presentedPassword) {
       return { hasAccess: false, canComment: false, canDownload: false, allowGuests: false, requiresPassword: true, link };
diff --git a/lib/stripe.ts b/lib/stripe.ts
new file mode 100644
index 0000000..6e68a1a
--- /dev/null
+++ b/lib/stripe.ts
@@ -0,0 +1,38 @@
+import Stripe from 'stripe';
+
+let stripeClient: Stripe | null = null;
+
+export function isStripeConfigured() {
+  return Boolean(process.env.STRIPE_SECRET_KEY && process.env.STRIPE_PRICE_ID);
+}
+
+export function getStripe() {
+  const secretKey = process.env.STRIPE_SECRET_KEY;
+  if (!secretKey) {
+    throw new Error('STRIPE_SECRET_KEY is not configured');
+  }
+
+  if (!stripeClient) {
+    stripeClient = new Stripe(secretKey);
+  }
+
+  return stripeClient;
+}
+
+export function getStripePriceId() {
+  const priceId = process.env.STRIPE_PRICE_ID;
+  if (!priceId) {
+    throw new Error('STRIPE_PRICE_ID is not configured');
+  }
+
+  return priceId;
+}
+
+export function getStripeWebhookSecret() {
+  const webhookSecret = process.env.STRIPE_WEBHOOK_SECRET;
+  if (!webhookSecret) {
+    throw new Error('STRIPE_WEBHOOK_SECRET is not configured');
+  }
+
+  return webhookSecret;
+}
diff --git a/package.json b/package.json
index 2400b4c..de74f65 100644
--- a/package.json
+++ b/package.json
@@ -44,6 +44,7 @@
     "react-window": "^2.2.7",
     "sharp": "^0.34.5",
     "sonner": "^2.0.7",
+    "stripe": "^20.4.1",
     "tailwind-merge": "^3.4.0",
     "tus-js-client": "^4.3.1",
     "tw-animate-css": "^1.4.0"
diff --git a/prisma/migrations/20260320110000_add_stripe_billing/migration.sql b/prisma/migrations/20260320110000_add_stripe_billing/migration.sql
new file mode 100644
index 0000000..574e2b4
--- /dev/null
+++ b/prisma/migrations/20260320110000_add_stripe_billing/migration.sql
@@ -0,0 +1,20 @@
+CREATE TYPE "BillingSubscriptionStatus" AS ENUM (
+  'FREE',
+  'TRIALING',
+  'ACTIVE',
+  'PAST_DUE',
+  'CANCELED',
+  'UNPAID',
+  'INCOMPLETE',
+  'INCOMPLETE_EXPIRED'
+);
+
+ALTER TABLE "users"
+ADD COLUMN "stripeCustomerId" TEXT,
+ADD COLUMN "stripeSubscriptionId" TEXT,
+ADD COLUMN "stripePriceId" TEXT,
+ADD COLUMN "stripeCurrentPeriodEnd" TIMESTAMP(3),
+ADD COLUMN "subscriptionStatus" "BillingSubscriptionStatus" NOT NULL DEFAULT 'FREE';
+
+CREATE UNIQUE INDEX "users_stripeCustomerId_key" ON "users"("stripeCustomerId");
+CREATE UNIQUE INDEX "users_stripeSubscriptionId_key" ON "users"("stripeSubscriptionId");
diff --git a/prisma/migrations/20260320123000_add_billing_trials_and_cleanup_dates/migration.sql b/prisma/migrations/20260320123000_add_billing_trials_and_cleanup_dates/migration.sql
new file mode 100644
index 0000000..578c3d5
--- /dev/null
+++ b/prisma/migrations/20260320123000_add_billing_trials_and_cleanup_dates/migration.sql
@@ -0,0 +1,7 @@
+ALTER TABLE "users"
+ADD COLUMN "trialEndsAt" TIMESTAMP(3),
+ADD COLUMN "billingAccessEndedAt" TIMESTAMP(3);
+
+UPDATE "users"
+SET "trialEndsAt" = "createdAt" + INTERVAL '7 days'
+WHERE "trialEndsAt" IS NULL;
diff --git a/prisma/migrations/20260321003000_add_subscription_cancel_state/migration.sql b/prisma/migrations/20260321003000_add_subscription_cancel_state/migration.sql
new file mode 100644
index 0000000..79c4227
--- /dev/null
+++ b/prisma/migrations/20260321003000_add_subscription_cancel_state/migration.sql
@@ -0,0 +1,3 @@
+ALTER TABLE "users"
+ADD COLUMN "stripeCancelAtPeriodEnd" BOOLEAN NOT NULL DEFAULT false,
+ADD COLUMN "stripeCancelAt" TIMESTAMP(3);
diff --git a/prisma/migrations/20260321094500_add_billing_trial_consumed_at/migration.sql b/prisma/migrations/20260321094500_add_billing_trial_consumed_at/migration.sql
new file mode 100644
index 0000000..43f2b91
--- /dev/null
+++ b/prisma/migrations/20260321094500_add_billing_trial_consumed_at/migration.sql
@@ -0,0 +1,6 @@
+ALTER TABLE "users"
+ADD COLUMN "billingTrialConsumedAt" TIMESTAMP(3);
+
+UPDATE "users"
+SET "billingTrialConsumedAt" = "trialEndsAt"
+WHERE "trialEndsAt" IS NOT NULL;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 17bff76..8008d32 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -22,6 +22,16 @@ model User {
   createdAt     DateTime  @default(now())
   updatedAt     DateTime  @updatedAt
   onboardingCompletedAt DateTime?
+  trialEndsAt DateTime?
+  billingTrialConsumedAt DateTime?
+  stripeCustomerId String? @unique
+  stripeSubscriptionId String? @unique
+  stripePriceId String?
+  stripeCurrentPeriodEnd DateTime?
+  stripeCancelAtPeriodEnd Boolean @default(false)
+  stripeCancelAt DateTime?
+  billingAccessEndedAt DateTime?
+  subscriptionStatus BillingSubscriptionStatus @default(FREE)
 
   // Relations
   accounts           Account[]
@@ -44,6 +54,17 @@ model User {
   @@map("users")
 }
 
+enum BillingSubscriptionStatus {
+  FREE
+  TRIALING
+  ACTIVE
+  PAST_DUE
+  CANCELED
+  UNPAID
+  INCOMPLETE
+  INCOMPLETE_EXPIRED
+}
+
 enum FeedbackEntryType {
   FEEDBACK
   REVIEW
diff --git a/scripts/bunny-orphan-cleanup.ts b/scripts/bunny-orphan-cleanup.ts
index 27a4732..3c7ee42 100644
--- a/scripts/bunny-orphan-cleanup.ts
+++ b/scripts/bunny-orphan-cleanup.ts
@@ -1,4 +1,5 @@
 import { db, disconnectDb } from '../lib/db';
+import { cleanupExpiredBillingWorkspaces } from './expired-billing-cleanup';
 
 const BUNNY_API_BASE = 'https://video.bunnycdn.com';
 const BUNNY_VIDEO_ID_PATTERN = /^[A-Za-z0-9_-]{8,128}$/;
@@ -197,6 +198,10 @@ async function main() {
   console.log(`[bunny-orphan-cleanup] Starting (${dryRun ? 'dry-run' : 'delete mode'})`);
   console.log(`[bunny-orphan-cleanup] Grace period: ${graceHours}h`);
 
+  const expiredBillingCleanup = await cleanupExpiredBillingWorkspaces({ dryRun });
+  console.log(`[bunny-orphan-cleanup] Expired owner workspaces scanned: ${expiredBillingCleanup.scanned}`);
+  console.log(`[bunny-orphan-cleanup] Expired owner workspaces deleted: ${expiredBillingCleanup.deleted}`);
+
   const { videos, scanned, skippedInvalid } = await listBunnyVideos(config);
   const eligible = videos.filter((video) => video.uploadedAt.getTime() <= cutoff);
   console.log(`[bunny-orphan-cleanup] Scanned: ${scanned}`);
diff --git a/scripts/expired-billing-cleanup.ts b/scripts/expired-billing-cleanup.ts
new file mode 100644
index 0000000..27f01d8
--- /dev/null
+++ b/scripts/expired-billing-cleanup.ts
@@ -0,0 +1,111 @@
+import { db } from '../lib/db';
+import { buildExpiredBillingWhereInput } from '../lib/billing';
+import { collectWorkspaceMediaUrls, deleteMediaFilesBestEffort } from '../lib/r2-cleanup';
+import { cleanupBunnyStreamVideosBestEffort } from '../lib/bunny-stream-cleanup';
+
+type ExpiredWorkspaceTarget = {
+  id: string;
+  ownerId: string;
+  ownerEmail: string | null;
+};
+
+async function getExpiredWorkspaceTargets(): Promise<ExpiredWorkspaceTarget[]> {
+  const expiredOwners = await db.user.findMany({
+    where: buildExpiredBillingWhereInput(),
+    select: { id: true },
+  });
+
+  if (expiredOwners.length === 0) {
+    return [];
+  }
+
+  return db.workspace.findMany({
+    where: {
+      ownerId: { in: expiredOwners.map((owner) => owner.id) },
+    },
+    select: {
+      id: true,
+      ownerId: true,
+      owner: {
+        select: {
+          email: true,
+        },
+      },
+    },
+  }).then((workspaces) =>
+    workspaces.map((workspace) => ({
+      id: workspace.id,
+      ownerId: workspace.ownerId,
+      ownerEmail: workspace.owner.email,
+    }))
+  );
+}
+
+export async function cleanupExpiredBillingWorkspaces(options?: { dryRun?: boolean }) {
+  const dryRun = options?.dryRun ?? false;
+  const workspaces = await getExpiredWorkspaceTargets();
+
+  if (workspaces.length === 0) {
+    return { scanned: 0, deleted: 0 };
+  }
+
+  let deleted = 0;
+
+  for (const workspace of workspaces) {
+    const [workspaceVersionRefs, workspaceAssetRefs, mediaUrls] = await Promise.all([
+      db.videoVersion.findMany({
+        where: {
+          video: {
+            project: {
+              workspaceId: workspace.id,
+            },
+          },
+        },
+        select: {
+          providerId: true,
+          videoId: true,
+        },
+      }),
+      db.videoAsset.findMany({
+        where: {
+          provider: 'BUNNY',
+          providerVideoId: { not: null },
+          video: {
+            project: {
+              workspaceId: workspace.id,
+            },
+          },
+        },
+        select: {
+          providerVideoId: true,
+        },
+      }),
+      collectWorkspaceMediaUrls(workspace.id),
+    ]);
+
+    if (dryRun) {
+      const ownerLabel = workspace.ownerEmail ?? workspace.ownerId;
+      console.log(
+        `[expired-billing-cleanup] Would delete workspace ${workspace.id} owned by ${ownerLabel}`
+      );
+      continue;
+    }
+
+    const bunnyRefs = [
+      ...workspaceVersionRefs,
+      ...workspaceAssetRefs.map((asset) => ({
+        providerId: 'bunny',
+        videoId: asset.providerVideoId as string,
+      })),
+    ];
+
+    await db.workspace.delete({ where: { id: workspace.id } });
+    await Promise.all([
+      cleanupBunnyStreamVideosBestEffort(bunnyRefs),
+      deleteMediaFilesBestEffort(mediaUrls),
+    ]);
+    deleted += 1;
+  }
+
+  return { scanned: workspaces.length, deleted };
+}
diff --git a/scripts/r2-orphan-cleanup.ts b/scripts/r2-orphan-cleanup.ts
index dff8b15..6dfa95e 100644
--- a/scripts/r2-orphan-cleanup.ts
+++ b/scripts/r2-orphan-cleanup.ts
@@ -1,6 +1,7 @@
 import { DeleteObjectCommand, ListObjectsV2Command, type ListObjectsV2CommandInput } from '@aws-sdk/client-s3';
 import { db, disconnectDb } from '../lib/db';
 import { r2Client, R2_BUCKET_NAME } from '../lib/r2';
+import { cleanupExpiredBillingWorkspaces } from './expired-billing-cleanup';
 
 const UNATTACHED_UPLOAD_TTL_MS = 15 * 60 * 1000;
 const CHUNK_SIZE = 500;
@@ -127,6 +128,10 @@ async function main() {
   const dryRun = process.argv.includes('--dry-run');
   console.log(`[r2-orphan-cleanup] Starting (${dryRun ? 'dry-run' : 'delete mode'})`);
 
+  const expiredBillingCleanup = await cleanupExpiredBillingWorkspaces({ dryRun });
+  console.log(`[r2-orphan-cleanup] Expired owner workspaces scanned: ${expiredBillingCleanup.scanned}`);
+  console.log(`[r2-orphan-cleanup] Expired owner workspaces deleted: ${expiredBillingCleanup.deleted}`);
+
   const { candidates, scanned } = await listCleanupCandidates();
   console.log(`[r2-orphan-cleanup] Scanned: ${scanned}, eligible (old enough): ${candidates.length}`);