What Feedback loop means
When a recipient presses the spam button, the provider learns something the sender does not. A feedback loop is the agreement that closes that gap: the provider returns a copy of the complained-about message, usually with the recipient's address redacted, to an address the sender has registered and proved control of.
The reports are formatted as ARF, the Abuse Reporting Format of RFC 5965 — a message/feedback-report part naming the type of complaint, carried alongside the original message. Enrolment is per provider and per sending address or domain, done through each provider's own postmaster pages; there is no single place to sign up, and several large providers offer aggregate reputation dashboards in place of per-message reports.
The only correct response to a complaint is immediate, permanent suppression of that recipient. Somebody who marked the mail as spam and keeps receiving it will mark it again, and complaint rate is among the signals every provider weighs. Acting on the reports is the entire point: an unread feedback loop mailbox is worse than none, because it means a provider is describing a problem nobody is fixing.
See it on your own domain. Every term in this glossary is something one of the eleven checks reads and reports.
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Related checks, definitions and guides.
- Spam trap The complaint that never reaches you.
- Bounce The other hygiene signal that has to be acted on.
- Blocklist Where an unhandled complaint rate eventually leads.
- How spam filters score a message What a filter weighs besides complaints.
- Testing inbox placement Measuring where mail lands before recipients react to it.