How to Fix Supabase Sign Up Not Working

1const { data, error } = await supabase.auth.signUp({
2  email: 'test@example.com',
3  password: 'securepassword123',
4})
5
6// Log the full response for debugging
7console.log('User:', data.user)
8console.log('Session:', data.session)
9console.log('Error:', error)
10
11// Common scenarios:
12// 1. user exists, session is null → Email confirmation is enabled, check inbox
13// 2. user is null, error exists → Check error.message
14// 3. user exists, session exists → Signup succeeded, email confirmation is disabled
15
16// Common error messages:
17// 'User already registered' → Email is taken
18// 'Password should be at least 6 characters' → Password too short
19// 'Signups not allowed for this instance' → Signups are disabled
20// 'Email rate limit exceeded' → Too many emails sent

1// Verify these match Dashboard > Settings > API
2const supabase = createClient(
3  'https://your-project-ref.supabase.co',  // Must match exactly
4  'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...' // Anon key, NOT service role key
5)
6
7// Common mistakes:
8// - Using 'http://' instead of 'https://'
9// - Trailing slash on the URL
10// - Using the service role key (starts with 'eyJ' but different value)
11// - Using keys from a different Supabase project
12// - Environment variables not loaded (undefined values)

1# Check these Dashboard settings:
2
3# 1. Dashboard > Authentication > Providers > Email
4#    - Is 'Confirm email' enabled? If yes, users must click the email link
5#    - For testing, you can temporarily disable it
6
7# 2. Dashboard > Authentication > Settings > SMTP
8#    - Default SMTP: 2 emails/hour limit
9#    - Configure custom SMTP (Resend, SendGrid, Mailgun) for production
10
11# 3. Dashboard > Authentication > URL Configuration
12#    - Site URL: your production URL (e.g., https://myapp.com)
13#    - Redirect URLs: add localhost for development
14#      e.g., http://localhost:3000/auth/callback
15
16# Quick test: disable 'Confirm email' temporarily
17# If signup works with it disabled, the issue is email delivery

1// Dashboard > Authentication > URL Configuration
2// Site URL: https://myapp.com
3// Redirect URLs:
4//   - http://localhost:3000/auth/callback
5//   - https://myapp.com/auth/callback
6//   - https://myapp.vercel.app/auth/callback
7
8// In your signUp call, specify the redirect:
9const { data, error } = await supabase.auth.signUp({
10  email: 'test@example.com',
11  password: 'securepassword123',
12  options: {
13    emailRedirectTo: 'http://localhost:3000/auth/callback',
14  },
15})
16
17// The callback page should handle the auth token exchange:
18// This is needed for PKCE flow used by SSR apps
19// See: how-to-set-up-supabase-auth-with-next-js

1-- Check if your trigger function has the correct security mode
2-- Security definer bypasses RLS (needed for triggers that insert into other tables)
3create or replace function public.handle_new_user()
4returns trigger
5language plpgsql
6security definer set search_path = ''
7as $$
8begin
9  insert into public.profiles (id, email)
10  values (new.id, new.email);
11  return new;
12end;
13$$;
14
15-- The trigger should be on auth.users
16create trigger on_auth_user_created
17  after insert on auth.users
18  for each row execute function public.handle_new_user();
19
20-- If using security invoker (default), you need an INSERT policy:
21create policy "Allow profile creation"
22on profiles for insert
23to authenticated
24with check (auth.uid() = id);
25
26-- Check if the trigger exists:
27-- Dashboard > Database > Triggers
28-- Or run in SQL Editor:
29select * from information_schema.triggers
30where trigger_name = 'on_auth_user_created';