What is Feedback Loop (FBL)?
Quick Answer
A system where mailbox providers forward spam complaints back to the sending email service.
Feedback loops are agreements between ESPs (email service providers) and mailbox providers (Gmail, Yahoo, Outlook) to automatically notify the sender when a recipient marks an email as spam. This allows the ESP to suppress the complaining address immediately. High complaint rates (above 0.1%) trigger spam filtering. MisarMail processes FBL reports in real time and auto-removes complainers from your list.
Related Terms
The percentage of recipients who mark your email as spam — a critical deliverability metric.
Email DeliverabilityThe percentage of emails that reach the recipient's inbox rather than the spam folder or being bounced.
Sender ReputationA score assigned by mailbox providers based on your sending patterns, determining whether your emails reach the inbox.
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