What are “trusted sender” programs at mailbox providers?

Major MBPs maintain relationships with high-volume, legitimate senders through informal trusted sender programs. These aren't formal certifications but relationship-based arrangements enabling better communication and issue resolution.

Trusted status typically requires: significant volume (millions monthly), strong historical metrics, proper authentication, and responsive abuse handling. MBPs invest relationship resources in senders whose volume makes individual attention worthwhile.

Benefits include: direct communication channels with postmaster teams, faster escalation for delivery issues, advance notice of policy changes, and sometimes beta access to new features. Building trusted status requires sustained excellent practices at meaningful scale.