IP Certification is a sending best practices program that helps ensuring that emails are received without being blocked by antispam filters or other email blocking systems.
Currently two providers offer IP Certification: Return Path and Certified Senders Alliance.
Certified senders are on allowlist which are used by global mailbox providers and email security companies. These commercial allowlists are based on a system that allows the sender to bypass antispam filters altogether or be assigned incremental points as they enter the system.
The Return Path Certification program offers a number of benefits, including the following:
The Certified Senders Alliance Certification offers amongst other benefits:
ISPs are free to use these services and the number of ISPs can vary depending on the allowlist.
However, because more and more ISPs build their antispam filters based on each inbox owner’s behavior rather than analyzing the message content itself, using IP Certification cannot be a guarantee of inbox placement or even delivery.