rfc8058-header-syntax

Anti-spam laws and compliance: CAN-SPAM, GDPR, CASL

List-Unsubscribe mailto vs https: Which Do ISPs Use in 2026?

Discover which List-Unsubscribe method ISPs actually use in 2026—mailto or https—and how to ensure your emails remain deliverable and compliant.

Anti-spam laws and compliance: CAN-SPAM, GDPR, CASL

List-Unsubscribe-Post Header Example and Exact Syntax 2026

See the exact syntax and real-world example of the List-Unsubscribe-Post header. Learn how to implement one-click unsubscribe in your emails, improve.