diff --git a/EXHAUSTIVE_TODO_LIST.md b/EXHAUSTIVE_TODO_LIST.md
index 6bf38ac06..57556b941 100644
--- a/EXHAUSTIVE_TODO_LIST.md
+++ b/EXHAUSTIVE_TODO_LIST.md
@@ -393,11 +393,11 @@ Critical path dependencies:
 ### Sub-Epic 1.4: API Versioning Strategy 🟢
 
 #### Task 1.4.1: Implement Version Headers
-- [ ] **Action 1.4.1.1**: Add `X-API-Version` header to all requests
+- [x] **Action 1.4.1.1**: Add `X-API-Version` header to all requests
   - **Scope**: `apps/web/src/services/api/client.ts` - Add header in request interceptor
   - **Dependencies**: None
   - **Risk**: LOW
-  - **Validation**: All requests include header
+  - **Validation**: ✅ Header added to request interceptor, uses env.API_VERSION
   - **Rollback**: Remove header
 
 - [ ] **Action 1.4.1.2**: Backend returns `X-API-Deprecated` header for old versions
@@ -414,11 +414,11 @@ Critical path dependencies:
   - **Validation**: Warning appears when deprecated version used
   - **Rollback**: Remove warning logic
 
-- [ ] **Action 1.4.1.4**: Store API version in config
+- [x] **Action 1.4.1.4**: Store API version in config
   - **Scope**: `apps/web/src/config/env.ts` - Add API_VERSION constant
   - **Dependencies**: None
   - **Risk**: LOW 🔒
-  - **Validation**: Version stored in config
+  - **Validation**: ✅ API_VERSION added to env config, defaults to 'v1'
   - **Rollback**: Remove from config
 
 - [ ] **Action 1.4.1.5**: Use config version in header
diff --git a/apps/web/src/config/env.ts b/apps/web/src/config/env.ts
index e7285d781..da7940915 100644
--- a/apps/web/src/config/env.ts
+++ b/apps/web/src/config/env.ts
@@ -8,6 +8,7 @@ const envSchema = z.object({
   VITE_STREAM_URL: z.string().url().default('ws://127.0.0.1:8082/stream'),
   VITE_UPLOAD_URL: z.string().url().default('http://127.0.0.1:8080/upload'),
   VITE_APP_NAME: z.string().default('Veza'),
+  VITE_API_VERSION: z.string().default('v1'),
   VITE_DEBUG: z
     .string()
     .transform((val) => val === 'true' || val === '1')
@@ -30,6 +31,7 @@ const parseEnv = () => {
       VITE_STREAM_URL: import.meta.env.VITE_STREAM_URL,
       VITE_UPLOAD_URL: import.meta.env.VITE_UPLOAD_URL,
       VITE_APP_NAME: import.meta.env.VITE_APP_NAME,
+      VITE_API_VERSION: import.meta.env.VITE_API_VERSION,
       VITE_DEBUG: import.meta.env.VITE_DEBUG,
     VITE_USE_MSW: import.meta.env.VITE_USE_MSW,
     VITE_FCM_VAPID_KEY: import.meta.env.VITE_FCM_VAPID_KEY,
@@ -58,6 +60,7 @@ export const env = {
   STREAM_URL: validatedEnv.VITE_STREAM_URL,
   UPLOAD_URL: validatedEnv.VITE_UPLOAD_URL,
   APP_NAME: validatedEnv.VITE_APP_NAME,
+  API_VERSION: validatedEnv.VITE_API_VERSION,
   DEBUG: validatedEnv.VITE_DEBUG,
   USE_MSW: validatedEnv.VITE_USE_MSW,
   FCM_VAPID_KEY: validatedEnv.VITE_FCM_VAPID_KEY,
diff --git a/apps/web/src/services/api/client.ts b/apps/web/src/services/api/client.ts
index 8e58230f6..bf43c1749 100644
--- a/apps/web/src/services/api/client.ts
+++ b/apps/web/src/services/api/client.ts
@@ -217,6 +217,11 @@ const processQueue = (error: Error | null, token: string | null = null) => {
 // CRITIQUE: Récupérer TOUJOURS le token frais depuis localStorage car Zustand peut ne pas être hydraté
 apiClient.interceptors.request.use(
   async (config: InternalAxiosRequestConfig) => {
+    // API Versioning: Add X-API-Version header to all requests
+    if (config.headers) {
+      config.headers['X-API-Version'] = env.API_VERSION;
+    }
+
     // INT-AUTH-004: Vérifier l'expiration du token avant d'envoyer la requête
     // Buffer de 60 secondes pour éviter les 401 inutiles
     const PRE_REQUEST_REFRESH_BUFFER_MS = 60 * 1000; // 60 secondes