Deliverability glossary · Updated 2026-10-27
One-click unsubscribe
Also called: RFC 8058
RFC 8058 one-click unsubscribe lets a mailbox provider opt a recipient out with a single POST request, no landing page and no confirmation step. Gmail and Yahoo require it from bulk senders.
It works through a companion header, `List-Unsubscribe-Post: List-Unsubscribe=One-Click`. When present alongside an HTTPS List-Unsubscribe URL, the provider POSTs to that URL directly when the recipient clicks unsubscribe in their interface.
The failure mode is specific and common: implementing the URL as a GET-only endpoint. The provider sends a POST, receives 405 Method Not Allowed, and the opt-out silently fails. The recipient believes they unsubscribed, keeps receiving mail, and reports spam the next time.
Correct behaviour is to accept POST at the same URL, process the opt-out without requiring a confirmation click, and return success. A landing page that asks "are you sure?" defeats the purpose and does not satisfy the requirement.
Because the address is embedded in a URL, it must be percent-encoded when written and decoded when handled. Plus signs in email addresses are the usual casualty.
How Raechly handles it
Campaigns that turn the Unsubscribe link on get the one-click header. Both GET and POST are registered on the unsubscribe route, with the address percent-encoded in the header URL and unescaped in the handler. It was shipped as a fix after a GET-only route returned 405 to real one-click requests. By default campaigns leave the header off and ask for a “stop” reply instead.
Related terms
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