Feedback Loop
Feedback loops pass spam complaints from mailbox providers back to senders, so complaining contacts can be suppressed when the report identifies them.
A feedback loop (FBL) is a complaint signal from a mailbox provider that tells you a recipient marked your email as spam.
When a recipient hits “Report spam,” the provider can send a notice back to the sender or sending platform with enough information to identify the complaining address or campaign. That lets the sender stop mailing that person and look at what triggered the complaint.
Providers do not all expose this the same way. Some share complaint data per message. Others offer aggregate complaint rates through dashboards or postmaster tools. Either way the purpose is the same: turn complaints into action before they accumulate against your sender reputation and email deliverability.
How teams use feedback loops
When a complaint identifies a contact, add them to a suppression list right away, review the message they received, and look for patterns by audience, signup source or campaign type. A cluster of complaints from one import or one form points at how those addresses were collected, but check the message they received as well.
Common mistakes
Treating complaint data as a report to read instead of a trigger to act on. If complaints are visible but the contact can still receive the next campaign, the system is not doing its job.