diff --git a/components/video-page/assets-pane.tsx b/components/video-page/assets-pane.tsx
index c2b50c0..58545cb 100644
--- a/components/video-page/assets-pane.tsx
+++ b/components/video-page/assets-pane.tsx
@@ -3,6 +3,7 @@
 import { memo, useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import * as tus from 'tus-js-client';
 import { toast } from 'sonner';
+import { toastApiError } from '@/lib/client/api-error';
 import {
   Download,
   FileVideo,
@@ -56,6 +57,7 @@ function formatTime(seconds: number): string {
 type UploadAudioResponse = {
   data?: { url?: string; reservationId?: string | null };
   error?: string;
+  code?: string;
 };
 
 function getAudioUploadValidationError(file: Blob): string | null {
@@ -369,10 +371,11 @@ export const AssetsPane = memo(function AssetsPane({
         const uploadPayload = (await uploadRes.json().catch(() => null)) as {
           data?: { url?: string; reservationId?: string | null };
           error?: string;
+          code?: string;
         } | null;
         const uploadedImageUrl = uploadPayload?.data?.url;
         if (!uploadRes.ok || !uploadedImageUrl) {
-          toast.error(`${file.name}: ${uploadPayload?.error || 'Failed to upload image'}`);
+          toastApiError(uploadPayload, 'Failed to upload image', { prefix: file.name });
           return false;
         }
 
@@ -385,7 +388,7 @@ export const AssetsPane = memo(function AssetsPane({
         return !!created;
       } catch (error) {
         console.error('Failed to upload image asset:', error);
-        toast.error(`${file.name}: Failed to upload image`);
+        toastApiError(error, 'Failed to upload image', { prefix: file.name });
         return false;
       }
     },
@@ -523,10 +526,11 @@ export const AssetsPane = memo(function AssetsPane({
             uploadToken: string;
           };
           error?: string;
+          code?: string;
         } | null;
 
         if (!initRes.ok || !initPayload?.data) {
-          toast.error(`${file.name}: ${initPayload?.error || 'Failed to initialize Bunny upload'}`);
+          toastApiError(initPayload, 'Failed to initialize Bunny upload', { prefix: file.name });
           return false;
         }
 
@@ -578,7 +582,7 @@ export const AssetsPane = memo(function AssetsPane({
         return true;
       } catch (error) {
         console.error('Failed to upload Bunny asset:', error);
-        toast.error(`${file.name}: Failed to upload Bunny video`);
+        toastApiError(error, 'Failed to upload Bunny video', { prefix: file.name });
         if (uploadedVideoId && uploadToken) {
           await fetch(`/api/videos/${videoId}/assets/bunny-init`, {
             method: 'DELETE',
@@ -631,7 +635,7 @@ export const AssetsPane = memo(function AssetsPane({
         return true;
       } catch (error) {
         console.error('Failed to upload R2 asset video:', error);
-        toast.error(`${file.name}: Failed to upload video`);
+        toastApiError(error, 'Failed to upload video', { prefix: file.name });
         return false;
       } finally {
         setIsUploadingBunny(false);
@@ -801,12 +805,12 @@ export const AssetsPane = memo(function AssetsPane({
         const uploadPayload = await readUploadAudioResponse(uploadRes);
         const uploadedUrl = uploadPayload?.data?.url;
         if (!uploadRes.ok || !uploadedUrl) {
-          toast.error(
-            `${fileName}: ${
-              uploadPayload?.error ||
-              (uploadRes.status === 413 ? MAX_AUDIO_UPLOAD_SIZE_MESSAGE : null) ||
-              'Failed to upload voice recording'
-            }`
+          toastApiError(
+            uploadPayload,
+            uploadRes.status === 413
+              ? MAX_AUDIO_UPLOAD_SIZE_MESSAGE
+              : 'Failed to upload voice recording',
+            { prefix: fileName }
           );
           return false;
         }
@@ -821,7 +825,7 @@ export const AssetsPane = memo(function AssetsPane({
         return !!created;
       } catch (error) {
         console.error('Failed to upload voice asset:', error);
-        toast.error(`${fileName}: Failed to upload voice recording`);
+        toastApiError(error, 'Failed to upload voice recording', { prefix: fileName });
         return false;
       }
     },
diff --git a/components/video-page/hooks/use-comment-actions.ts b/components/video-page/hooks/use-comment-actions.ts
index 02ce4e4..097e125 100644
--- a/components/video-page/hooks/use-comment-actions.ts
+++ b/components/video-page/hooks/use-comment-actions.ts
@@ -28,6 +28,7 @@ import {
 } from '@/components/video-page/image-upload-utils';
 import { validateAnnotationStrokes } from '@/lib/validation';
 import { withWebmDuration } from '@/lib/webm-duration';
+import { ApiRequestError, apiRequestError, toastApiError } from '@/lib/client/api-error';
 
 interface UseCommentActionsParams extends CommentActionsConfig {
   setVideo: Dispatch<SetStateAction<VideoData | null>>;
@@ -61,17 +62,6 @@ function getAudioUploadFilename(blob: Blob): string {
   return 'recording.webm';
 }
 
-/**
- * A step of the submit that failed with something worth reading out.
- *
- * The attachment goes up before the comment does, so a full account fails on the
- * image and never reaches the comment at all. Reporting that as "failed to add
- * comment" tells the uploader to try again, which is the one thing that cannot
- * work. Carried as its own error type so a network fault, which has no message
- * anybody wants to see, still falls back to the generic line.
- */
-class CommentSubmitError extends Error {}
-
 export function useCommentActions({
   videoId,
   setVideo,
@@ -192,7 +182,7 @@ export function useCommentActions({
       } | null;
       const token = payload?.data?.token;
       if (!response.ok || !token) {
-        throw new Error(payload?.error || 'Failed to prepare upload');
+        throw apiRequestError(payload, 'Failed to prepare upload');
       }
       return token;
     },
@@ -274,10 +264,14 @@ export function useCommentActions({
           });
 
           if (!imageRes.ok) {
+            // The attachment goes up before the comment does, so a full account
+            // fails here and never reaches the comment at all. Thrown with the
+            // code attached so the catch below can offer the way out.
             const imagePayload = (await imageRes.json().catch(() => null)) as {
               error?: string;
+              code?: string;
             } | null;
-            throw new CommentSubmitError(imagePayload?.error || 'Failed to upload image');
+            throw apiRequestError(imagePayload, 'Failed to upload image');
           }
           const imageDataResponse = await imageRes.json();
           imageData = { url: imageDataResponse.data.url };
@@ -336,8 +330,11 @@ export function useCommentActions({
               ),
             };
           });
-          const payload = (await res.json().catch(() => null)) as { error?: string } | null;
-          toast.error(payload?.error || 'Failed to add comment');
+          const payload = (await res.json().catch(() => null)) as {
+            error?: string;
+            code?: string;
+          } | null;
+          toastApiError(payload, 'Failed to add comment');
         }
       } catch (error) {
         setVideo((prev) => {
@@ -351,7 +348,9 @@ export function useCommentActions({
             ),
           };
         });
-        toast.error(error instanceof CommentSubmitError ? error.message : 'Failed to add comment');
+        // A network fault has no message anybody wants to see, so only an
+        // ApiRequestError speaks for itself; toastApiError falls back for the rest.
+        toastApiError(error instanceof ApiRequestError ? error : null, 'Failed to add comment');
       } finally {
         setIsSubmittingComment(false);
         setIsUploadingImage(false);
diff --git a/components/video-page/hooks/use-version-actions.ts b/components/video-page/hooks/use-version-actions.ts
index f24ee1c..727ab11 100644
--- a/components/video-page/hooks/use-version-actions.ts
+++ b/components/video-page/hooks/use-version-actions.ts
@@ -12,6 +12,7 @@ import {
 import type { VersionActionsConfig, VideoData } from '@/components/video-page/types';
 import { resolvePublicBunnyCdnHostname } from '@/lib/bunny-cdn';
 import { cleanupPendingR2VideoUpload, uploadVideoToR2 } from '@/lib/client/r2-video-upload';
+import { apiRequestError, toastApiError } from '@/lib/client/api-error';
 
 /** What a failed version upload has to undo, depending on which provider it started on. */
 type PendingVersionCleanup =
@@ -113,7 +114,13 @@ export function useVersionActions({
       body: JSON.stringify({ title, sizeBytes: file.size.toString() }),
     });
 
-    if (!initRes.ok) throw new Error('Failed to initialize upload');
+    if (!initRes.ok) {
+      const initPayload = (await initRes.json().catch(() => null)) as {
+        error?: string;
+        code?: string;
+      } | null;
+      throw apiRequestError(initPayload, 'Failed to initialize upload');
+    }
     const {
       data: { videoId: bunnyVideoId, libraryId, signature, expirationTime, uploadToken },
     } = await initRes.json();
@@ -236,7 +243,7 @@ export function useVersionActions({
 
       if (!res.ok) {
         const data = await res.json().catch(() => null);
-        throw new Error(data?.error || 'Failed to create version');
+        throw apiRequestError(data, 'Failed to create version');
       }
 
       const versionData = await res.json();
@@ -277,7 +284,7 @@ export function useVersionActions({
         }
       }
       console.error('Failed to create version:', errorObj);
-      toast.error(errorObj.message || 'Failed to create version');
+      toastApiError(errorObj, 'Failed to create version');
     } finally {
       setIsCreatingVersion(false);
       setNewVersionUploadProgress(0);
diff --git a/components/video-page/hooks/use-video-assets.ts b/components/video-page/hooks/use-video-assets.ts
index 5442fcc..f5d4317 100644
--- a/components/video-page/hooks/use-video-assets.ts
+++ b/components/video-page/hooks/use-video-assets.ts
@@ -3,6 +3,7 @@
 import { useCallback, useEffect, useRef, useState } from 'react';
 import { toast } from 'sonner';
 import type { VideoAsset } from '@/components/video-page/types';
+import { apiRequestError, toastApiError } from '@/lib/client/api-error';
 
 type BunnyDownloadPreference = 'original' | 'compressed';
 
@@ -43,6 +44,7 @@ interface AssetsListResponse {
 interface AssetCreateResponse {
   data?: VideoAsset;
   error?: string;
+  code?: string;
 }
 
 const ASSET_PAGE_SIZE = 40;
@@ -185,7 +187,7 @@ export function useVideoAssets({
         });
         const body = (await res.json().catch(() => null)) as AssetCreateResponse | null;
         if (!res.ok || !body?.data) {
-          toast.error(body?.error || 'Failed to create asset');
+          toastApiError(body, 'Failed to create asset');
           return null;
         }
 
@@ -288,7 +290,7 @@ export function useVideoAssets({
       } | null;
       const token = payload?.data?.token;
       if (!response.ok || !token) {
-        throw new Error(payload?.error || 'Failed to prepare upload');
+        throw apiRequestError(payload, 'Failed to prepare upload');
       }
       return token;
     },
diff --git a/lib/api-response.ts b/lib/api-response.ts
index 6afa021..3053cbd 100644
--- a/lib/api-response.ts
+++ b/lib/api-response.ts
@@ -67,6 +67,12 @@ export const ErrorCode = {
 
   // Storage errors
   STORAGE_LIMIT_EXCEEDED: 'STORAGE_LIMIT_EXCEEDED',
+  /**
+   * Out of room because the account has not paid, rather than because the plan
+   * is full. Its own code so the client can offer the upgrade, which is the
+   * actual remedy here and is no help at all on the paid ceiling.
+   */
+  TRIAL_STORAGE_LIMIT_EXCEEDED: 'TRIAL_STORAGE_LIMIT_EXCEEDED',
 } as const;
 
 /**
@@ -175,4 +181,13 @@ export const apiErrors = {
   storageExceeded: (
     message = 'Storage limit exceeded. Please delete some files to free up space.'
   ) => errorResponse(message, HttpStatus.INSUFFICIENT_STORAGE, ErrorCode.STORAGE_LIMIT_EXCEEDED),
+
+  /**
+   * The same 507, for an account that is out of room because it is on the free
+   * trial. Telling this caller to delete files is advice that does not apply:
+   * they have three gigabytes because they have not subscribed, not because they
+   * have filled two hundred.
+   */
+  trialStorageExceeded: (message: string) =>
+    errorResponse(message, HttpStatus.INSUFFICIENT_STORAGE, ErrorCode.TRIAL_STORAGE_LIMIT_EXCEEDED),
 };
diff --git a/lib/client/api-error.ts b/lib/client/api-error.ts
new file mode 100644
index 0000000..e659015
--- /dev/null
+++ b/lib/client/api-error.ts
@@ -0,0 +1,101 @@
+// What a failed API call is worth showing the person who made it.
+//
+// Every route answers with `{ error, code? }`, and the code is the part that
+// says whether there is anything the caller can do. Losing it on the way to a
+// toast is how a full trial account ends up reading "Failed to upload" and
+// trying the same upload again.
+
+import { toast } from 'sonner';
+
+/** The machine-readable half of an error response. Mirrors ErrorCode in lib/api-response.ts. */
+export const API_ERROR_CODES = {
+  /** Out of room because the account has not subscribed, not because the plan is full. */
+  TRIAL_STORAGE_LIMIT_EXCEEDED: 'TRIAL_STORAGE_LIMIT_EXCEEDED',
+} as const;
+
+export interface ApiErrorPayload {
+  error?: string;
+  code?: string;
+}
+
+/**
+ * A failure that came back from our own API, with the code still attached.
+ *
+ * The upload helpers throw rather than return, so without this the code is gone
+ * by the time anything is in a position to show it.
+ */
+export class ApiRequestError extends Error {
+  readonly code: string | null;
+
+  constructor(message: string, code?: string | null) {
+    super(message);
+    this.name = 'ApiRequestError';
+    this.code = code ?? null;
+  }
+}
+
+/** Builds the error to throw from a parsed `{ error, code }` body. */
+export function apiRequestError(
+  payload: ApiErrorPayload | null,
+  fallback: string
+): ApiRequestError {
+  return new ApiRequestError(payload?.error || fallback, payload?.code);
+}
+
+function codeOf(source: unknown): string | null {
+  if (source instanceof ApiRequestError) return source.code;
+  if (source && typeof source === 'object' && 'code' in source) {
+    const code = (source as ApiErrorPayload).code;
+    return typeof code === 'string' ? code : null;
+  }
+  return null;
+}
+
+function messageOf(source: unknown, fallback: string): string {
+  if (source instanceof Error) return source.message || fallback;
+  if (source && typeof source === 'object' && 'error' in source) {
+    const message = (source as ApiErrorPayload).error;
+    if (typeof message === 'string' && message) return message;
+  }
+  return fallback;
+}
+
+export interface ToastApiErrorOptions {
+  /** Prepended as `${prefix}: ${message}`, for per-file failures in a batch. */
+  prefix?: string;
+}
+
+/**
+ * Shows an API failure, with a way out attached when there is one.
+ *
+ * Takes either a parsed response body or a thrown error, so the same call works
+ * whether the caller checked `res.ok` itself or caught what an upload helper
+ * threw. On the trial storage ceiling it adds a link to the billing settings,
+ * because subscribing is the only thing that makes the upload possible and the
+ * uploader has no way to know that from "storage limit exceeded".
+ */
+export function toastApiError(
+  source: unknown,
+  fallback: string,
+  options: ToastApiErrorOptions = {}
+): void {
+  const message = messageOf(source, fallback);
+  const text = options.prefix ? `${options.prefix}: ${message}` : message;
+
+  if (codeOf(source) === API_ERROR_CODES.TRIAL_STORAGE_LIMIT_EXCEEDED) {
+    toast.error(text, {
+      // Longer than a plain error: this one is asking for a decision rather than
+      // just reporting, and it disappears under the cursor at the usual timing.
+      duration: 12000,
+      action: {
+        label: 'See plans',
+        onClick: () => {
+          window.location.href = '/settings';
+        },
+      },
+    });
+    return;
+  }
+
+  toast.error(text);
+}
diff --git a/lib/client/project-video-upload.ts b/lib/client/project-video-upload.ts
index bc93ba7..ad6939a 100644
--- a/lib/client/project-video-upload.ts
+++ b/lib/client/project-video-upload.ts
@@ -3,6 +3,7 @@
 import { resolvePublicBunnyCdnHostname } from '@/lib/bunny-cdn';
 import { cleanupPendingR2VideoUpload, uploadVideoToR2 } from '@/lib/client/r2-video-upload';
 import type { DirectUploadProvider } from '@/components/video-page/types';
+import { apiRequestError } from '@/lib/client/api-error';
 
 export const VIDEO_FILE_EXTENSIONS = ['mp4', 'webm', 'ogg', 'mov', 'm4v', 'mkv'];
 
@@ -143,7 +144,7 @@ export async function uploadProjectVideo(
       } | null;
 
       if (!createResponse.ok) {
-        throw new Error(createPayload?.error || 'Failed to create video');
+        throw apiRequestError(createPayload, 'Failed to create video');
       }
 
       pendingCleanup = null;
@@ -171,7 +172,7 @@ export async function uploadProjectVideo(
     } | null;
 
     if (!initResponse.ok || !initPayload?.data) {
-      throw new Error(initPayload?.error || 'Failed to initialize upload');
+      throw apiRequestError(initPayload, 'Failed to initialize upload');
     }
 
     const { videoId, libraryId, signature, expirationTime, uploadToken } = initPayload.data;
@@ -243,7 +244,7 @@ export async function uploadProjectVideo(
     } | null;
 
     if (!createResponse.ok) {
-      throw new Error(createPayload?.error || 'Failed to create video');
+      throw apiRequestError(createPayload, 'Failed to create video');
     }
 
     pendingCleanup = null;
diff --git a/lib/client/r2-asset-video-upload.ts b/lib/client/r2-asset-video-upload.ts
index de1a87f..1db211e 100644
--- a/lib/client/r2-asset-video-upload.ts
+++ b/lib/client/r2-asset-video-upload.ts
@@ -1,4 +1,5 @@
 import { captureVideoThumbnail } from '@/lib/client/video-thumbnail';
+import { apiRequestError } from '@/lib/client/api-error';
 import { uploadBytesWithProgress, type UploadProgressHandler } from '@/lib/client/r2-video-upload';
 
 export type R2AssetVideoInitResponse = {
@@ -39,7 +40,7 @@ export async function initR2AssetVideoUpload(
     error?: string;
   } | null;
   if (!initRes.ok || !initPayload?.data) {
-    throw new Error(initPayload?.error || 'Failed to initialize video upload');
+    throw apiRequestError(initPayload, 'Failed to initialize video upload');
   }
 
   return initPayload.data;
diff --git a/lib/client/r2-video-upload.ts b/lib/client/r2-video-upload.ts
index c82ba2f..c91e5e5 100644
--- a/lib/client/r2-video-upload.ts
+++ b/lib/client/r2-video-upload.ts
@@ -1,4 +1,5 @@
 import { captureVideoThumbnail } from '@/lib/client/video-thumbnail';
+import { apiRequestError } from '@/lib/client/api-error';
 import {
   getMultipartProgressPercent,
   getPartByteRange,
@@ -151,7 +152,7 @@ async function completeMultipartUpload(
 
   if (!res.ok) {
     const payload = (await res.json().catch(() => null)) as { error?: string } | null;
-    throw new Error(payload?.error || 'Failed to complete multipart upload');
+    throw apiRequestError(payload, 'Failed to complete multipart upload');
   }
 }
 
@@ -243,7 +244,7 @@ export async function initR2VideoUpload(
     error?: string;
   } | null;
   if (!initRes.ok || !initPayload?.data) {
-    throw new Error(initPayload?.error || 'Failed to initialize video upload');
+    throw apiRequestError(initPayload, 'Failed to initialize video upload');
   }
 
   return initPayload.data;
diff --git a/tests/api/bunny-upload-reservation.test.ts b/tests/api/bunny-upload-reservation.test.ts
index 6d36bc8..ce6811d 100644
--- a/tests/api/bunny-upload-reservation.test.ts
+++ b/tests/api/bunny-upload-reservation.test.ts
@@ -16,9 +16,15 @@ import {
 } from '@/app/api/projects/[projectId]/videos/bunny-init/route';
 import { POST as createAsset } from '@/app/api/videos/[videoId]/assets/route';
 import { UPLOAD_RESERVATION_PURPOSES } from '@/lib/storage-quota';
+import { PLAN_STORAGE_LIMIT_BYTES } from '@/lib/storage-quota';
 import { apiRequest, callRoute, readData, readError } from '../helpers/request';
 import { signedInAs } from '../helpers/session';
-import { createVideo, seedProject } from '../factories';
+import {
+  createSubscribedUser,
+  createUploadReservation,
+  createVideo,
+  seedProject,
+} from '../factories';
 
 const GIB = BigInt(1024) * BigInt(1024) * BigInt(1024);
 
@@ -261,3 +267,65 @@ describe('a Bunny hold cannot be consumed by another flow', () => {
     expect(second.status).toBe(507);
   });
 });
+
+// What a refusal says, and to whom.
+//
+// A trial account is out of room because it has not subscribed, so "delete some
+// files" is advice that does not apply and the upgrade is the only way through.
+// The two cases carry different codes because the client offers a link on one of
+// them and must not on the other.
+describe('what the storage refusal says', () => {
+  it('names the trial ceiling and its own code for an unpaid account', async () => {
+    const scenario = await seedProject();
+    signedInAs(scenario.owner);
+
+    const response = await initUpload(scenario.project.id, BigInt(4) * GIB);
+
+    expect(response.status).toBe(507);
+    const body = (await response.json()) as { error: string; code: string };
+    expect(body.code).toBe('TRIAL_STORAGE_LIMIT_EXCEEDED');
+    expect(body.error).toContain('3 GB');
+    expect(body.error).toContain('Upgrade');
+  });
+
+  it('tells a paying account to free up space instead', async () => {
+    const scenario = await seedProject({ ownerUser: await createSubscribedUser() });
+    signedInAs(scenario.owner);
+
+    // Full at the paid ceiling rather than the trial one.
+    await createUploadReservation({
+      billedUserId: scenario.owner.id,
+      sizeBytes: PLAN_STORAGE_LIMIT_BYTES - BigInt(1024),
+    });
+
+    const response = await initUpload(scenario.project.id, BigInt(1) * GIB);
+
+    expect(response.status).toBe(507);
+    const body = (await response.json()) as { error: string; code: string };
+    expect(body.code).toBe('STORAGE_LIMIT_EXCEEDED');
+    expect(body.error).toContain('delete some files');
+  });
+});
+
+// Asked directly: five one-gigabyte uploads started at once against a three
+// gigabyte trial. Whether they go up in one piece or in parts makes no
+// difference, because r2-init takes the reservation before it decides on
+// multipart, and bunny-init holds one for the size the client declared.
+describe('several uploads started at once', () => {
+  it('grants only the ones that fit and refuses the rest', async () => {
+    const scenario = await seedProject();
+    signedInAs(scenario.owner);
+
+    const results = await Promise.all(
+      Array.from({ length: 5 }, () => initUpload(scenario.project.id, BigInt(1) * GIB))
+    );
+
+    const granted = results.filter((response) => response.status === 200);
+    const refused = results.filter((response) => response.status === 507);
+
+    // Two fit: the check is >=, so the third would land exactly on 3 GiB.
+    expect(granted).toHaveLength(2);
+    expect(refused).toHaveLength(3);
+    expect(await db.uploadReservation.count()).toBe(2);
+  });
+});