Email Deliverability 6 min read Aug 25, 2026

Feedback Loops (FBL) and List-Unsubscribe Headers: Protecting Sender Reputation

Published by ZodHost Engineering Team

Executive Summary & Key Takeaways

Implement RFC 8058 one-click List-Unsubscribe headers and register ISP Feedback Loops to keep spam complaint rates below 0.1%.

Automating Complaint Suppression

Receiving Feedback Loop notifications allows email systems to immediately suppress users who mark messages as spam, maintaining clean sender scores.

Tags: #Feedback Loops FBL #List Unsubscribe header #one click unsubscribe RFC 8058 #spam complaint rate #email sender score

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