Deliverability
Reputation, list quality, bounces, and inbox placement.
3 topics in this category.
About this category
This section collects production-verified specifications, implementation standards, and operational guidelines for deliverability. Each specification provides clear compliance levels (Required, Recommended, Optional, or Avoid) alongside concrete testing methods and platform considerations.
Topics
Reverse DNS (PTR) & Forward-Confirmed Reverse DNS (FCrDNS)
RequiredConfigure Forward-Confirmed Reverse DNS (FCrDNS) on every sending IP address, ensuring the PTR record matches the forward A/AAAA record and the SMTP EHLO greeting.
Mailing List Hygiene & Recipient Validation
RequiredMaintain pristine sender reputation through automated bounce management, double opt-in confirmation, inactive subscriber sunsetting, and spam trap avoidance.
Spam Complaint Handling & Feedback Loops (FBL)
RequiredProcess user spam complaints in real-time through ISP Feedback Loops (FBL) and RFC 5965 Abuse Reporting Format (ARF) to maintain spam complaint rates below 0.10%.