All glossary entries
Glossary
Feedback loop (FBL)
A formal channel through which mailbox providers send "this user complained" notifications back to the sender.
When a recipient hits "report spam" in their mail client, most major providers (Gmail via Postmaster Tools, Outlook via SNDS, Yahoo via direct FBL) send the sending platform a notification with the offending message details.
BoomSauce ingests these via the SendGrid event webhook and writes them as `complained` events on the relevant mt_sends row. The address is auto-suppressed and the sending mailbox's complaint rate updates.
You can't opt out of feedback loops — and you shouldn't want to. They're the most direct signal of how recipients perceive your sending.
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