Postmaster Tools (Google)

Google Postmaster Tools is a free, native Google service that helps senders monitor and improve email delivery performance to Gmail users. The platform provides detailed insights into email delivery metrics including spam rates, domain and IP reputation, authentication status, encryption, and delivery errors. Data is displayed with a 48-hour delay and only includes Gmail recipients. Features include reputation monitoring, authentication feedback, delivery error analysis, and spam complaint tracking. Access requires a Gmail account and verification of domain ownership.