SMTP

Use Lumail SMTP when an application can only send through SMTP and cannot call POST /api/v1/emails directly.

The endpoint is designed for low-volume transactional email: authentication codes, magic links, password resets, account invitations, receipts, and operational notifications. SMTP messages are accepted by the Lumail SMTP adapter, authenticated with a Lumail API token, then queued through the transactional priority lane.

Connection Settings

Setting	Value
Host	smtp.lumail.io
Port	587
Security	STARTTLS
Username	Your organization slug, or any label
Password	A Lumail API token
From	An address on a verified Lumail domain

The password is not your Lumail account password. Create an API token from Settings -> API Tokens and store it in your application's secret manager.

Setup Checklist

1. Verify the sending domain in Lumail.
2. Create a Lumail API token in the same organization.
3. Configure your app to use smtp.lumail.io on port 587 with STARTTLS.
4. Use a From address on the verified domain.
5. Send one test email before enabling the integration in production.

For the full setup flow, use the SMTP transactional email tutorial.

Supabase Auth

Supabase Auth custom SMTP can use these values:

Host: smtp.lumail.io
Port: 587
Security: STARTTLS
Username: your-org-slug
Password: lum_your_api_token
Sender email: [email protected]

If your application supports HTTP hooks, prefer POST /api/v1/emails. The HTTP API returns structured errors and avoids SMTP/MIME parsing.

Related Documentation