# Send Supabase Auth email with Bird SMTP

Use [Bird SMTP](/smtp-service) to send the authentication emails your Supabase application creates. Supabase manages the templates and authentication links; Bird handles email submission and delivery reporting.

## Before you start

- Have permission to change your Supabase project's Auth settings.
- Verify a [sending domain](/docs/guides/email/sending-domains) in Bird and choose a From address on that domain.
- Create a Bird API key with the `emails` scope. Use a separate key for this application so you can manage its SMTP settings independently.

## Connect the SMTP service

1. Open your project's **Authentication** settings and enable **Custom SMTP**. Supabase's [SMTP configuration guide](https://supabase.com/docs/guides/auth/auth-smtp) identifies the current settings location.
2. Enter the sender name and your verified From address.
3. Enter these connection values, selecting the host that matches your Bird key's region.

| Setting  | Value                                                               |
| -------- | ------------------------------------------------------------------- |
| Host     | `eu1.smtp.bird.com` for an EU key; `us1.smtp.bird.com` for a US key |
| Port     | `465`                                                               |
| Username | `bird`                                                              |
| Password | Your Bird API key                                                   |

Port 465 uses implicit TLS. See the [connection settings](/docs/guides/email/smtp#connection-settings) for the transport contract and supported alternatives.

Save the settings. Review your project's authentication rate limits and allowed redirect URLs before testing.
In Bird's **Email** > **SMTP** settings, select this application's key and turn off click tracking for authentication email. This keeps sign-in URLs in the form generated by your authentication service. Keep the message category transactional.

## Verify a complete sign-in

Use an address you control to request a confirmation or password-reset email from your application. Find the message in the [Email log](/docs/guides/email/email-log), check its recipient and delivery events, then follow its authentication link and verify the expected application screen.

A completed SMTP submission starts the delivery process. The email log and the completed sign-in establish the subsequent outcomes. Test the application's expiry and resend behavior separately before sending to customers.

## Resolve setup failures

| Symptom                                     | Check                                                                                                                         |
| ------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------- |
| SMTP authentication fails                   | Match the key region to the host, use username `bird`, and check the key's email scope.                                       |
| The sender is rejected                      | Use a From address on the verified domain in the same Bird workspace.                                                         |
| Supabase refuses another email request      | Inspect Supabase Auth logs and its configured rate limits.                                                                    |
| Bird accepted the message but it is missing | Inspect recipient events, suppressions, and the receiving mailbox.                                                            |
| The email arrives but sign-in fails         | Review the Supabase redirect allowlist, link expiry, and application callback; check click tracking is disabled for this key. |

## Next steps

- [SMTP configuration and responses](/docs/guides/email/smtp).
- [Email delivery events](/docs/guides/email/events).
- [Email API](/email-api) for messages your application sends outside its authentication flow.

## Related resources

- [Getting started with email](/learn/email/getting-started-with-email) (video)
- [Build your first integration](/learn/paths/integration) (course)
- [Send your first email](/docs/get-started/send-your-first-email) (docs)

[Get an implementation brief](/learn/workspace?topic=email)