diff --git a/tfjm/helloasso.py b/tfjm/helloasso.py
index 768fe88..bbd0b66 100644
--- a/tfjm/helloasso.py
+++ b/tfjm/helloasso.py
@@ -12,49 +12,63 @@ _refresh_token = None
 _expires_at = None
 
 
+def _get_hello_asso_api_base_url():
+    if not settings.DEBUG:
+        return "https://api.helloasso.com"
+    else:
+        return "https://api.helloasso-sandbox.com"
+
+
 def get_hello_asso_access_token():
     global _access_token, _refresh_token, _expires_at
 
+    base_url = _get_hello_asso_api_base_url()
+
     now = datetime.now()
     if _access_token is None:
         response = requests.post(
-            "https://api.helloasso.com/oauth2/token",
+            f"{base_url}/oauth2/token",
             data={
                 "grant_type": "client_credentials",
                 "client_id": settings.HELLOASSO_CLIENT_ID,
                 "client_secret": settings.HELLOASSO_CLIENT_SECRET,
             },
         )
-        response.raise_for_status()
-        data = response.json()
-        _access_token = data["access_token"]
-        _refresh_token = data["refresh_token"]
-        _expires_at = now + timedelta(seconds=data["expires_in"])
     elif now >= _expires_at:
         response = requests.post(
-            "https://api.helloasso.com/oauth2/token",
+            f"{base_url}/oauth2/token",
             data={
                 "grant_type": "refresh_token",
                 "refresh_token": _refresh_token,
             },
         )
-        response.raise_for_status()
-        data = response.json()
-        _access_token = data["access_token"]
-        _refresh_token = data["refresh_token"]
-        _expires_at = now + timedelta(seconds=data["expires_in"])
+    else:
+        return _access_token
+
+    if response.status_code == 400:
+        raise ValueError(str(response.json()['errors']))
+    response.raise_for_status()
+
+    data = response.json()
+    _access_token = data["access_token"]
+    _refresh_token = data["refresh_token"]
+    _expires_at = now + timedelta(seconds=data["expires_in"])
 
     return _access_token
 
 
 def get_checkout_intent(checkout_id):
+    base_url = _get_hello_asso_api_base_url()
     token = get_hello_asso_access_token()
+
     response = requests.get(
-        f"https://api.helloasso.com/v5/organizations/animath/checkout-intents/{checkout_id}",
+        f"{base_url}/v5/organizations/animath/checkout-intents/{checkout_id}",
         headers={"Authorization": f"Bearer {token}"},
     )
     if response.status_code == 404:
         return None
+    elif response.status_code == 400:
+        raise ValueError(str(response.json()['errors']))
     response.raise_for_status()
 
     checkout_intent = response.json()
@@ -65,10 +79,12 @@ def get_checkout_intent(checkout_id):
 
 
 def create_checkout_intent(amount, name, back_url, error_url, return_url, contains_donation=False, metadata=None):
+    base_url = _get_hello_asso_api_base_url()
     token = get_hello_asso_access_token()
+
     metadata = metadata or {}
     response = requests.post(
-        "https://api.helloasso.com/v5/organizations/animath/checkout-intents/",
+        f"{base_url}/v5/organizations/animath/checkout-intents/",
         headers={"Authorization": f"Bearer {token}"},
         json={
             "totalAmount": amount,
@@ -81,6 +97,7 @@ def create_checkout_intent(amount, name, back_url, error_url, return_url, contai
             "metadata": metadata,
         },
     )
-    print(response.text)
+    if response.status_code == 400:
+        raise ValueError(str(response.json()['errors']))
     response.raise_for_status()
     return response.json()
diff --git a/tfjm/settings.py b/tfjm/settings.py
index 130f551..6fa4177 100644
--- a/tfjm/settings.py
+++ b/tfjm/settings.py
@@ -30,8 +30,11 @@ ADMINS = [("Emmy D'Anello", "emmy.danello@animath.fr")]
 # SECURITY WARNING: keep the secret key used in production secret!
 SECRET_KEY = os.getenv('DJANGO_SECRET_KEY', 'CHANGE_ME_IN_ENV_SETTINGS')
 
+# dev in development mode, prod in production mode
+TFJM_STAGE = os.getenv('TFJM_STAGE', 'dev')
+
 # SECURITY WARNING: don't run with debug turned on in production!
-DEBUG = True
+DEBUG = TFJM_STAGE != "prod"
 
 SITE_ID = 1
 
@@ -76,7 +79,7 @@ if "test" not in sys.argv:  # pragma: no cover
         'mailer',
     ]
 
-if os.getenv("TFJM_STAGE", "dev") == "prod":  # pragma: no cover
+if TFJM_STAGE == "prod":  # pragma: no cover
     INSTALLED_APPS += [
         'channels_redis',
     ]
@@ -277,7 +280,7 @@ CHANNEL_LAYERS = {
     }
 }
 
-if os.getenv("TFJM_STAGE", "dev") == "prod":  # pragma: no cover
+if TFJM_STAGE == "prod":  # pragma: no cover
     from .settings_prod import *  # noqa: F401,F403
 else:
     from .settings_dev import *  # noqa: F401,F403