Mail services#
| Service | Notes |
|---|---|
| SMTP2GO | The default and recommended. EU or US region. |
| SendGrid, Mailgun, Postmark, Brevo, Mailjet, Resend | API key. Each service's address is fixed in the code, so the key can only ever go there. |
| Other SMTP service | Host and port with an API key or app password, always over STARTTLS. |
| Your own relay | For example an SMTP relay in your Azure. Can be used without signing in, which is less secure: a dedicated service is recommended. |
- The key goes into your Key Vault and is read only by the Function App's identity.
- Give the key permission to send and nothing else.
- Link and open tracking are turned off where the service allows, because they rewrite the enrol links.
- Changing mail service during an upgrade keeps the old one working until the new version is published.