diff --git a/backend/main.py b/backend/main.py
index 6b1966f..af6904b 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -76,21 +76,26 @@ def database_status():
 
 # users
 
-
 @app.post("/create-user")
 def api_create_user(user: UserCreate):
 
-    user_id = create_user(
-        user.username,
-        user.password
-    )
+    try:
+        user_id = create_user(
+            user.username,
+            user.password
+        )
+
+    except sqlite3.IntegrityError:
+        raise HTTPException(
+            status_code=409,
+            detail="username already exists"
+        )
 
     return {
         "status": "created",
         "user_id": user_id
     }
 
-
 @app.post("/login")
 def api_login(login: Login):