Supabase Auth

Supabase’s built-in mailer is heavily rate limited and only meant for testing. Point it at SpacePost to send confirmation, magic link, invite and password reset emails from your own domain.

1. Verify your domain in SpacePost and create an API key (sending_access, restricted to that domain is ideal).

2. In the Supabase dashboard open Authentication, then Emails (or Project Settings, Authentication) and find SMTP Settings. Turn on Enable custom SMTP.

3. Fill in:

   Field	Value
   Sender email	no-reply@acme.com (on your verified domain)
   Sender name	Acme
   Host	smtp.spacepost.dev
   Port number	25976
   Username	spacepost
   Password	your SpacePost API key

   Supabase upgrades the connection with STARTTLS on this port automatically.

4. Save, then raise the rate limit for emails in Authentication, Rate Limits if you expect more than the default.

5. Trigger a sign-up or password reset and check the email in the SpacePost dashboard under Emails.

Tip

Edit Supabase’s email templates under Authentication, Emails, Templates to match your brand. Keep the confirmation link variable ({{ .ConfirmationURL }}) intact.

If emails do not arrive: check the SpacePost email log for a 403 invalid_from_address (sender domain not verified) or a suppression; and confirm the key was pasted without spaces.