diff --git a/docker-compose.yml b/docker-compose.yml
index 590aa0c..79e7a58 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -24,7 +24,7 @@ services:
       APP_ENV: development
       FRONTEND_ORIGIN: http://localhost:3000
     ports:
-      - "8001:8000"
+      - "8000:8000"
     depends_on:
       - postgres
       - redis
@@ -34,9 +34,13 @@ services:
   frontend:
     build: ./frontend
     environment:
-      VITE_API_BASE_URL: http://localhost:8000
+      VITE_ALLOWED_HOST: prof.open-squared.tech
+      VITE_DEV_API_PROXY_TARGET: http://backend:8000
+      VITE_HMR_HOST: prof.open-squared.tech
+      VITE_HMR_PROTOCOL: wss
+      VITE_HMR_CLIENT_PORT: 443
     ports:
-      - "3001:3000"
+      - "3000:3000"
     depends_on:
       - backend
     volumes:
diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 7d38afa..c003afa 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -2,6 +2,33 @@ import React, { useEffect, useMemo, useRef, useState } from 'react'
 
 const API_BASE = '/api'
 
+async function parseApiResponse(res) {
+  const contentType = res.headers.get('content-type') || ''
+  const bodyText = await res.text()
+  const isJson = contentType.includes('application/json')
+  const data = isJson && bodyText ? JSON.parse(bodyText) : null
+
+  if (!res.ok) {
+    const detail =
+      data?.detail ||
+      data?.message ||
+      bodyText.trim() ||
+      `Erreur API (${res.status})`
+    throw new Error(detail)
+  }
+
+  if (!isJson) {
+    throw new Error(`Réponse API invalide (${res.status})`)
+  }
+
+  return data
+}
+
+async function apiFetch(path, options) {
+  const res = await fetch(`${API_BASE}${path}`, options)
+  return parseApiResponse(res)
+}
+
 function Avatar({ speaking }) {
   return (
     <div className="avatar-shell">
@@ -59,6 +86,7 @@ export default function App() {
   const [isRecording, setIsRecording] = useState(false)
   const [isTranscribing, setIsTranscribing] = useState(false)
   const [voiceStatus, setVoiceStatus] = useState('')
+  const [errorMessage, setErrorMessage] = useState('')
   const recognitionRef = useRef(null)
   const mediaRecorderRef = useRef(null)
   const mediaStreamRef = useRef(null)
@@ -90,33 +118,50 @@ export default function App() {
   }, [])
 
   async function loadStudents() {
-    const res = await fetch(`${API_BASE}/students`)
-    const data = await res.json()
-    setStudents(data)
-    if (data.length && !selectedStudentId) {
-      setSelectedStudentId(String(data[0].id))
+    try {
+      setErrorMessage('')
+      const data = await apiFetch('/students')
+      setStudents(data)
+      if (data.length && !selectedStudentId) {
+        setSelectedStudentId(String(data[0].id))
+      }
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de charger les élèves.')
     }
   }
 
   async function createStudent(e) {
     e.preventDefault()
-    const res = await fetch(`${API_BASE}/students`, {
-      method: 'POST',
-      headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ ...form, age: Number(form.age) }),
-    })
-    const data = await res.json()
-    await loadStudents()
-    setSelectedStudentId(String(data.id))
+    if (!form.first_name.trim()) {
+      setErrorMessage('Le prénom est obligatoire.')
+      return
+    }
+
+    try {
+      setErrorMessage('')
+      const data = await apiFetch('/students', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ ...form, first_name: form.first_name.trim(), age: Number(form.age) }),
+      })
+      await loadStudents()
+      setSelectedStudentId(String(data.id))
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de créer l’élève.')
+    }
   }
 
   async function startSession() {
     if (!selectedStudentId) return
-    const res = await fetch(`${API_BASE}/session/start?student_id=${selectedStudentId}`, { method: 'POST' })
-    const data = await res.json()
-    appendMessage('assistant', data.reply)
-    speak(data.reply)
-    await loadProgress(selectedStudentId)
+    try {
+      setErrorMessage('')
+      const data = await apiFetch(`/session/start?student_id=${selectedStudentId}`, { method: 'POST' })
+      appendMessage('assistant', data.reply)
+      speak(data.reply)
+      await loadProgress(selectedStudentId)
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de démarrer la séance.')
+    }
   }
 
   function appendMessage(role, content) {
@@ -129,48 +174,64 @@ export default function App() {
     const text = input.trim()
     appendMessage('user', text)
     setInput('')
-    const res = await fetch(`${API_BASE}/chat`, {
-      method: 'POST',
-      headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ student_id: Number(selectedStudentId), message: text }),
-    })
-    const data = await res.json()
-    appendMessage('assistant', data.reply)
-    speak(data.reply)
+    try {
+      setErrorMessage('')
+      const data = await apiFetch('/chat', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ student_id: Number(selectedStudentId), message: text }),
+      })
+      appendMessage('assistant', data.reply)
+      speak(data.reply)
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible d’envoyer le message.')
+    }
   }
 
   async function loadProgress(studentId) {
-    const res = await fetch(`${API_BASE}/progress/${studentId}`)
-    const data = await res.json()
-    setProgress(data.progress || [])
+    try {
+      setErrorMessage('')
+      const data = await apiFetch(`/progress/${studentId}`)
+      setProgress(data.progress || [])
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de charger la progression.')
+    }
   }
 
   async function fetchAssessment() {
     if (!selectedStudentId) return
-    const res = await fetch(`${API_BASE}/assessment/next/${selectedStudentId}`)
-    const data = await res.json()
-    setAssessment(data)
-    setAssessmentAnswer('')
+    try {
+      setErrorMessage('')
+      const data = await apiFetch(`/assessment/next/${selectedStudentId}`)
+      setAssessment(data)
+      setAssessmentAnswer('')
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de charger le mini-test.')
+    }
   }
 
   async function submitAssessment(e) {
     e.preventDefault()
     if (!assessment || !assessmentAnswer.trim()) return
-    const res = await fetch(`${API_BASE}/assessment/answer`, {
-      method: 'POST',
-      headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({
-        student_id: Number(selectedStudentId),
-        skill_code: assessment.skill_code,
-        answer: assessmentAnswer,
-      }),
-    })
-    const data = await res.json()
-    appendMessage('assistant', `Quiz: ${data.feedback}`)
-    speak(data.feedback)
-    setAssessment(null)
-    setAssessmentAnswer('')
-    await loadProgress(selectedStudentId)
+    try {
+      setErrorMessage('')
+      const data = await apiFetch('/assessment/answer', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          student_id: Number(selectedStudentId),
+          skill_code: assessment.skill_code,
+          answer: assessmentAnswer,
+        }),
+      })
+      appendMessage('assistant', `Quiz: ${data.feedback}`)
+      speak(data.feedback)
+      setAssessment(null)
+      setAssessmentAnswer('')
+      await loadProgress(selectedStudentId)
+    } catch (error) {
+      setErrorMessage(error.message || 'Impossible de valider la réponse.')
+    }
   }
 
   function speak(text) {
@@ -203,17 +264,10 @@ export default function App() {
     setVoiceStatus('Transcription en cours...')
 
     try {
-      const res = await fetch(`${API_BASE}/transcribe`, {
+      const data = await apiFetch('/transcribe', {
         method: 'POST',
         body: formData,
       })
-
-      if (!res.ok) {
-        const error = await res.json().catch(() => ({}))
-        throw new Error(error.detail || 'La transcription a échoué.')
-      }
-
-      const data = await res.json()
       setInput(data.text || '')
       setVoiceStatus(data.text ? 'Texte dicté prêt à être envoyé.' : 'Aucun texte reconnu.')
     } catch (error) {
@@ -416,7 +470,8 @@ export default function App() {
         </form>
 
         {voiceStatus && <p className="muted voice-status">{voiceStatus}</p>}
+        {errorMessage && <p className="muted voice-status">{errorMessage}</p>}
       </main>
     </div>
   )
-}
\ No newline at end of file
+}
diff --git a/frontend/vite.config.js b/frontend/vite.config.js
index 08dba1b..a32acd7 100644
--- a/frontend/vite.config.js
+++ b/frontend/vite.config.js
@@ -1,10 +1,32 @@
-import { defineConfig } from 'vite'
+import { defineConfig, loadEnv } from 'vite'
 import react from '@vitejs/plugin-react'
 
-export default defineConfig({
-  plugins: [react()],
-  server: {
-    host: true,
-    allowedHosts: ['prof.open-squared.tech']
+export default defineConfig(({ mode }) => {
+  const env = loadEnv(mode, process.cwd(), '')
+  const allowedHost = env.VITE_ALLOWED_HOST || 'prof.open-squared.tech'
+  const proxyTarget = env.VITE_DEV_API_PROXY_TARGET || 'http://backend:8000'
+  const hmrHost = env.VITE_HMR_HOST
+  const hmrProtocol = env.VITE_HMR_PROTOCOL
+  const hmrClientPort = env.VITE_HMR_CLIENT_PORT ? Number(env.VITE_HMR_CLIENT_PORT) : undefined
+
+  return {
+    plugins: [react()],
+    server: {
+      host: true,
+      allowedHosts: [allowedHost],
+      proxy: {
+        '/api': {
+          target: proxyTarget,
+          changeOrigin: true,
+        },
+      },
+      hmr: hmrHost
+        ? {
+            host: hmrHost,
+            protocol: hmrProtocol || 'ws',
+            clientPort: hmrClientPort,
+          }
+        : undefined,
+    },
   }
 })