diff --git a/backend/app/main.py b/backend/app/main.py
index 3ce90e5..459e89a 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -81,7 +81,7 @@ async def auth_callback(payload: AuthCallbackRequest):
         "grant_type": "authorization_code",
         "code": payload.code,
         "code_verifier": payload.code_verifier,
-        "redirect_uri": str(payload.redirect_uri),
+        "redirect_uri": payload.redirect_uri,
     }
 
     # Some OIDC providers expect client credentials via HTTP Basic auth
diff --git a/backend/app/schemas.py b/backend/app/schemas.py
index 0772077..07e2b53 100644
--- a/backend/app/schemas.py
+++ b/backend/app/schemas.py
@@ -12,7 +12,7 @@ class ChatRequest(BaseModel):
 class AuthCallbackRequest(BaseModel):
     code: str
     code_verifier: str
-    redirect_uri: HttpUrl
+    redirect_uri: str
 
 class AuthConfigResponse(BaseModel):
     issuer: HttpUrl