diff --git a/client/src/lib/queryClient.ts b/client/src/lib/queryClient.ts
index 56f2fae..aac81aa 100644
--- a/client/src/lib/queryClient.ts
+++ b/client/src/lib/queryClient.ts
@@ -20,6 +20,29 @@ export function handleUnauthorized(url: string) {
   window.location.href = "/login";
 }
 
+/**
+ * Extrait un message lisible d'une erreur d'API.
+ * apiRequest lève des erreurs de la forme `500: {"error":"…"}` : sans ce
+ * décodage, l'interface ne peut afficher qu'un message générique alors que le
+ * serveur a renvoyé la cause exacte.
+ */
+export function getErrorMessage(error: unknown, fallback: string): string {
+  if (!(error instanceof Error) || !error.message) return fallback;
+
+  const withoutStatus = error.message.replace(/^\d{3}:\s*/, '').trim();
+  if (!withoutStatus) return fallback;
+
+  try {
+    const parsed = JSON.parse(withoutStatus);
+    const message = parsed?.error || parsed?.message;
+    if (typeof message === 'string' && message.trim()) return message.trim();
+  } catch {
+    // Corps non-JSON : on affiche le texte tel quel
+  }
+
+  return withoutStatus.startsWith('<') ? fallback : withoutStatus;
+}
+
 async function throwIfResNotOk(res: Response, url: string) {
   if (!res.ok) {
     if (res.status === 401) {
diff --git a/client/src/pages/mobile/new-post.tsx b/client/src/pages/mobile/new-post.tsx
index 985d2a2..9cbf6a1 100644
--- a/client/src/pages/mobile/new-post.tsx
+++ b/client/src/pages/mobile/new-post.tsx
@@ -32,7 +32,7 @@ import { Checkbox } from "@/components/ui/checkbox";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { Dialog, DialogContent } from "@/components/ui/dialog";
 import { useToast } from "@/hooks/use-toast";
-import { apiRequest, queryClient, handleUnauthorized } from "@/lib/queryClient";
+import { apiRequest, queryClient, handleUnauthorized, getErrorMessage } from "@/lib/queryClient";
 import type { SocialPage, Media, ScheduledPost } from "@shared/schema";
 import { PreviewModal } from "@/components/preview-modal";
 import { DateTimePicker } from "@/components/datetime-picker";
@@ -230,10 +230,10 @@ export default function NewPostMobile() {
       });
       queryClient.invalidateQueries({ queryKey: ['/api/ai/generations'] });
     },
-    onError: () => {
+    onError: (error: unknown) => {
       toast({
         title: "Erreur",
-        description: "Impossible de générer le texte",
+        description: getErrorMessage(error, "Impossible de générer le texte"),
         variant: "destructive",
       });
     },
diff --git a/client/src/pages/mobile/remotion-video.tsx b/client/src/pages/mobile/remotion-video.tsx
index 90a7043..c3d09ed 100644
--- a/client/src/pages/mobile/remotion-video.tsx
+++ b/client/src/pages/mobile/remotion-video.tsx
@@ -13,7 +13,7 @@ import Sidebar from "@/components/sidebar";
 import { Checkbox } from "@/components/ui/checkbox";
 import { DateTimePicker } from "@/components/datetime-picker";
 import { useQuery, useMutation } from "@tanstack/react-query";
-import { apiRequest, queryClient, handleUnauthorized } from "@/lib/queryClient";
+import { apiRequest, queryClient, handleUnauthorized, getErrorMessage } from "@/lib/queryClient";
 import type { Media, SocialPage } from "@shared/schema";
 import { SiFacebook, SiTiktok } from "react-icons/si";
 
@@ -91,7 +91,7 @@ export default function MobileRemotionVideoPage() {
   const generateTextMutation = useMutation({
     mutationFn: async (text: string) => (await apiRequest('POST', '/api/reels/generate-text', { productInfo: text })).json(),
     onSuccess: (data: any) => { setGeneratedVariants(data.variants || []); toast({ title: "Textes générés" }); },
-    onError: () => toast({ title: "Erreur IA", variant: "destructive" }),
+    onError: (error: unknown) => toast({ title: "Erreur IA", description: getErrorMessage(error, "Impossible de générer le texte"), variant: "destructive" }),
   });
 
   const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
diff --git a/client/src/pages/new-post.tsx b/client/src/pages/new-post.tsx
index 80af7be..3cec2e6 100644
--- a/client/src/pages/new-post.tsx
+++ b/client/src/pages/new-post.tsx
@@ -31,7 +31,7 @@ import { Checkbox } from "@/components/ui/checkbox";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
 import { Dialog, DialogContent } from "@/components/ui/dialog";
 import { useToast } from "@/hooks/use-toast";
-import { apiRequest, queryClient, handleUnauthorized } from "@/lib/queryClient";
+import { apiRequest, queryClient, handleUnauthorized, getErrorMessage } from "@/lib/queryClient";
 import { MediaThumbnail } from "@/components/media-thumbnail";
 import type { SocialPage, Media, ScheduledPost } from "@shared/schema";
 import { PreviewModal } from "@/components/preview-modal";
@@ -226,10 +226,10 @@ export default function NewPost() {
       });
       queryClient.invalidateQueries({ queryKey: ['/api/ai/generations'] });
     },
-    onError: () => {
+    onError: (error: unknown) => {
       toast({
         title: "Erreur",
-        description: "Impossible de générer le texte",
+        description: getErrorMessage(error, "Impossible de générer le texte"),
         variant: "destructive",
       });
     },
diff --git a/client/src/pages/new-reel.tsx b/client/src/pages/new-reel.tsx
index adb0753..e72e897 100644
--- a/client/src/pages/new-reel.tsx
+++ b/client/src/pages/new-reel.tsx
@@ -25,7 +25,7 @@ import {
     SelectValue,
 } from "@/components/ui/select";
 import { useToast } from "@/hooks/use-toast";
-import { apiRequest, queryClient, handleUnauthorized } from "@/lib/queryClient";
+import { apiRequest, queryClient, handleUnauthorized, getErrorMessage } from "@/lib/queryClient";
 import type { SocialPage, Media } from "@shared/schema";
 import { SiFacebook, SiTiktok } from "react-icons/si";
 import { MediaThumbnail } from "@/components/media-thumbnail";
@@ -235,10 +235,10 @@ export default function NewReel() {
                 description: `${variants.length} variations créées`,
             });
         },
-        onError: () => {
+        onError: (error: unknown) => {
             toast({
                 title: "Erreur",
-                description: "Impossible de générer le texte",
+                description: getErrorMessage(error, "Impossible de générer le texte"),
                 variant: "destructive",
             });
         },
diff --git a/client/src/pages/remotion-video.tsx b/client/src/pages/remotion-video.tsx
index 3df0661..6371bec 100644
--- a/client/src/pages/remotion-video.tsx
+++ b/client/src/pages/remotion-video.tsx
@@ -8,7 +8,7 @@ import { Textarea } from "@/components/ui/textarea";
 import { UploadCloud, Video, Loader2, Check, Sparkles, Mic, Volume2, Music, Play, Pause, Send } from "lucide-react";
 import { Slider } from "@/components/ui/slider";
 import { useQuery, useMutation } from "@tanstack/react-query";
-import { apiRequest, queryClient, handleUnauthorized } from "@/lib/queryClient";
+import { apiRequest, queryClient, handleUnauthorized, getErrorMessage } from "@/lib/queryClient";
 import { Label } from "@/components/ui/label";
 import { Switch } from "@/components/ui/switch";
 import { Checkbox } from "@/components/ui/checkbox";
@@ -93,7 +93,7 @@ export default function RemotionVideoPage() {
       setGeneratedVariants(data.variants || []);
       toast({ title: "Textes générés", description: "Cliquez pour appliquer." });
     },
-    onError: () => toast({ title: "Erreur IA", variant: "destructive" }),
+    onError: (error: unknown) => toast({ title: "Erreur IA", description: getErrorMessage(error, "Impossible de générer le texte"), variant: "destructive" }),
   });
 
   const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
diff --git a/server/routes.ts b/server/routes.ts
index dabb47e..40780a0 100644
--- a/server/routes.ts
+++ b/server/routes.ts
@@ -9,7 +9,7 @@ import multer from "multer";
 import bcrypt from "bcrypt";
 import passport from "./auth";
 import { z } from "zod";
-import { openRouterService } from "./services/openrouter";
+import { openRouterService, describeGenerationError } from "./services/openrouter";
 import { minioService as cloudinaryService, buildMinioUrl } from "./services/minio";
 import { insertPostSchema, insertScheduledPostSchema, insertSocialPageSchema, insertAiGenerationSchema, insertCloudinaryConfigSchema, updateCloudinaryConfigSchema, insertOpenrouterConfigSchema, updateOpenrouterConfigSchema, insertUserSchema, postMedia, type SocialPage } from "@shared/schema";
 import type { User, InsertUser, ScheduledPost } from "@shared/schema";
@@ -631,7 +631,8 @@ export async function registerRoutes(app: Express): Promise<Server> {
       res.json({ variants: generatedTexts });
     } catch (error) {
       console.error("Error generating text:", error);
-      res.status(500).json({ error: "Failed to generate text" });
+      const { status, message } = describeGenerationError(error);
+      res.status(status).json({ error: message });
     }
   });
 
diff --git a/server/routes/reels.ts b/server/routes/reels.ts
index eeca4fa..5522aa0 100644
--- a/server/routes/reels.ts
+++ b/server/routes/reels.ts
@@ -9,7 +9,7 @@ import { ffmpegService } from '../services/ffmpeg';
 import { facebookService } from '../services/facebook';
 import { tiktokService } from '../services/tiktok';
 import { minioService as cloudinaryService, buildMinioUrl, resolveInternalUrl } from '../services/minio';
-import { openRouterService } from '../services/openrouter';
+import { openRouterService, describeGenerationError } from '../services/openrouter';
 import { db } from '../db';
 import { cloudinaryConfig } from '@shared/schema';
 import { eq } from 'drizzle-orm';
@@ -254,7 +254,8 @@ reelsRouter.post('/reels/generate-text', async (req: Request, res: Response) =>
         res.json({ variants: generatedTexts });
     } catch (error) {
         console.error('❌ Error generating Reel text:', error);
-        res.status(500).json({ error: 'Erreur lors de la génération du texte' });
+        const { status, message } = describeGenerationError(error);
+        res.status(status).json({ error: message });
     }
 });
 
diff --git a/server/services/openrouter.ts b/server/services/openrouter.ts
index 2137458..98d2fc5 100644
--- a/server/services/openrouter.ts
+++ b/server/services/openrouter.ts
@@ -15,6 +15,49 @@ interface GeneratedText {
 import crypto from 'crypto';
 import { storage } from '../storage';
 
+/**
+ * Extrait le message d'erreur d'une réponse OpenRouter, qu'elle soit au format
+ * JSON ({ error: { message } }) ou en texte brut. Tronqué pour éviter de
+ * déverser une page HTML entière dans l'interface.
+ */
+function extractUpstreamMessage(body: string): string {
+  const trimmed = (body || '').trim();
+  if (!trimmed) return 'aucun détail fourni';
+
+  try {
+    const parsed = JSON.parse(trimmed);
+    const message = parsed?.error?.message || parsed?.message || parsed?.error;
+    if (typeof message === 'string' && message.trim()) {
+      return message.trim().slice(0, 300);
+    }
+  } catch {
+    // Réponse non-JSON (page d'erreur HTML d'un proxy, par exemple)
+  }
+
+  return trimmed.replace(/\s+/g, ' ').slice(0, 300);
+}
+
+/**
+ * Traduit une erreur de génération en réponse HTTP exploitable côté interface.
+ * Sans cela, l'utilisateur ne voit qu'un 500 générique alors que la cause
+ * (configuration absente, clé invalide, crédits épuisés) est connue du serveur.
+ */
+export function describeGenerationError(error: unknown): { status: number; message: string } {
+  const message = error instanceof Error ? error.message : 'Erreur inconnue lors de la génération';
+
+  // Problème de configuration : l'administrateur peut le corriger lui-même
+  if (/Configuration OpenRouter non trouvée|Clé API OpenRouter manquante/.test(message)) {
+    return { status: 400, message };
+  }
+
+  // Refus du service tiers
+  if (/OpenRouter a refusé la requête|Réponse invalide de l'API OpenRouter/.test(message)) {
+    return { status: 502, message };
+  }
+
+  return { status: 500, message };
+}
+
 export class OpenRouterService {
   private baseUrl = "https://openrouter.ai/api/v1/chat/completions";
 
@@ -64,7 +107,13 @@ export class OpenRouterService {
       if (!response.ok) {
         const errorText = await response.text();
         console.error('OpenRouter API Error Response:', errorText);
-        throw new Error(`OpenRouter API error: ${response.status} ${response.statusText}`);
+        // Le motif renvoyé par OpenRouter (clé invalide, crédits épuisés, modèle
+        // inconnu…) est la seule information exploitable : on le fait remonter
+        // jusqu'à l'utilisateur, qui n'a pas accès aux logs du serveur.
+        throw new Error(
+          `OpenRouter a refusé la requête (${response.status} ${response.statusText}) ` +
+          `avec le modèle "${modelToUse}" : ${extractUpstreamMessage(errorText)}`
+        );
       }
 
       const data = await response.json();