Even when you send through SMTP from your CRM or your own application, every commercial message in 2026 must include a working one-click unsubscribe mechanism. Mailpro’s SMTP relay handles this automatically — both the visible link inside the body and the technical headers Gmail, Yahoo and Outlook now require.
Two unsubscribe layers in every SMTP message
| Layer | Where it lives | Who sees it |
|---|---|---|
| List-Unsubscribe header | In the email headers (invisible) | Gmail, Yahoo, Outlook unsubscribe button |
| List-Unsubscribe-Post header | RFC 8058 one-click | Same providers, automatic one-click |
| Visible unsubscribe link | In the email footer | Every recipient |
How Mailpro injects the unsubscribe link
When the SMTP relay accepts your message, it scans the body for a placeholder (e.g. {unsubscribe} or %%unsubscribe%%) and replaces it with a unique, signed URL pointing to a Mailpro-hosted opt-out page. If the placeholder is missing, Mailpro can append a small «Unsubscribe» line at the very end of the HTML to keep you compliant.
Configuring the unsubscribe behaviour
Open Account → SMTP → Unsubscribe settings. You control:
- Whether to inject a link automatically (default: yes)
- The placeholder string to look for in your body
- The destination page after unsubscribe (Mailpro default or your custom URL)
- Whether to also send a confirmation email
- Whether to add the RFC 8058 one-click headers (default: yes)
Suppression list and re-subscriptions
Every unsubscribe is recorded in your account’s suppression list. Future SMTP sends to the same address are blocked at the relay level — you cannot accidentally email someone who unsubscribed. The user can re-subscribe themselves from the Mailpro-hosted page; you cannot reactivate an unsubscribed address by hand.
Custom branding
You can host the unsubscribe page on your own domain via CNAME, change the page’s look-and-feel, and decide whether to require a confirmation click. The signed token in the URL stays valid for 30 days — long enough for a forwarded email, short enough to prevent abuse.
How to test
Send a real SMTP message to a Gmail and an Outlook account you own. Check both: a) the visible link in the footer, b) the «Unsubscribe» button next to the sender name (Gmail) or in the menu (Outlook). Both should land on a Mailpro page and complete the opt-out instantly.
Stay compliant on every SMTP send
Mailpro’s unsubscribe management covers the visible link, the RFC 8058 headers, the suppression list and the audit trail. Read the full SMTP unsubscribe FAQ and the RFC 8058 explainer.