# Database error saving new user

> Sign-ups fail with "Database error saving new user". It is almost always a trigger on auth.users failing. How to find the broken trigger in Studio and fix it.

Source: https://supahost.app/kb/database-error-saving-new-user · Updated 2026-11-11

## What you see

`supabase.auth.signUp()` fails with a 500 response. The same thing can happen on a first OAuth sign-in, an invite, or **Add user** in Studio:

```json
{ "code": 500, "error_code": "unexpected_failure", "msg": "Database error saving new user" }
```

supabase-js raises it as an `AuthApiError` with that message. After an OAuth sign-in it arrives in the redirect URL instead, as `error_description=Database+error+saving+new+user`.

## Why it happens

Creating a user means inserting a row into `auth.users`. If anything in that insert fails, Postgres rolls it back and Auth replies with this generic message. The real Postgres error never reaches the client.

The cause is nearly always a trigger on `auth.users`, typically `on_auth_user_created` calling `public.handle_new_user()` to create a profile row. Ways it breaks:

- The function isn't `security definer`, so it runs as Auth's role, `supabase_auth_admin`, which has no rights on `public.profiles`.
- It sets `search_path = ''` (correct) but writes to `profiles` instead of `public.profiles`, which gives `relation "profiles" does not exist`.
- `profiles` has a `not null` column the function doesn't fill, or a unique column (such as `username`) that a second user collides with.
- It depends on a metadata key that some sign-up paths don't send. `new.raw_user_meta_data ->> 'full_name'` is set by your sign-up form but may be missing for GitHub users or invites.
- A column was renamed or dropped after the function was written.

## How to fix it

1. Open Studio (Dashboard → your project → **Database** tab → **Open Studio**) and go to the SQL editor.
2. List the triggers on `auth.users`:

   ```sql
   select tgname, pg_get_triggerdef(oid) as definition
   from pg_trigger
   where tgrelid = 'auth.users'::regclass and not tgisinternal;
   ```

3. Read the function each trigger calls:

   ```sql
   select pg_get_functiondef('public.handle_new_user'::regproc);
   ```

4. Reproduce the failure where you can see the real error. Insert a fake user inside a transaction and roll it back:

   ```sql
   begin;
   insert into auth.users (id, email, raw_user_meta_data)
   values (gen_random_uuid(), 'qa_signup_test@example.com', '{"full_name": "QA Test"}');
   rollback;
   ```

   The SQL editor now shows the actual error: permission denied, missing relation, null value or duplicate key. If your role isn't allowed to insert into `auth.users`, run the `insert into public.profiles ...` statement from the function body by hand instead.

5. Fix the function. This version covers the common failures:

   ```sql
   create or replace function public.handle_new_user()
   returns trigger
   language plpgsql
   security definer
   set search_path = ''
   as $$
   begin
     insert into public.profiles (id, display_name)
     values (
       new.id,
       coalesce(new.raw_user_meta_data ->> 'full_name', split_part(new.email, '@', 1))
     )
     on conflict (id) do nothing;
     return new;
   end;
   $$;
   ```

6. Sign up again from your app to confirm.

If the profile row is useful but not essential, you can wrap the insert in a `begin ... exception when others then ... end` block so a profile bug never blocks sign-ups. Record the failure in a table you check, or users will quietly end up without profiles.

## On SupaHost

- The project **Logs** tab isn't available yet, so reproducing the insert in the SQL editor (step 4) is the quickest way to see the underlying error.
- On Business and Enterprise you can read the Auth service's log over SSH with `sudo supahost-logs app-one auth`. The Postgres error usually appears there next to the 500.
- Only the instance owner can open Studio. Team members can see the project but can't run these queries.

## Related

- [Triggers](/docs/database/triggers)
- [Users and the auth schema](/docs/auth/users)
- [NEW is null in a trigger function](/kb/new-is-null-in-trigger)
- [Errors creating, updating or deleting users](/kb/dashboard-user-errors)