Postmaster+
Email verification and deliverability monitoring.
Postmaster+ is an email intelligence and deliverability platform that helps senders validate addresses, enrich contact records, and maintain sender compliance. It combines real-time email verification with engagement scoring and data enrichment, while monitoring DNS configuration, authentication, complaint rates, mailbox provider reputation, and blocklist status. A free compliance scan checks a sending domain against Google and Yahoo sender guidelines.
Core capabilities include SPF, DKIM, DMARC, TLS, and IP rDNS monitoring; complaint rate tracking with custom thresholds; and reputation data from Gmail Postmaster Tools, Outlook SNDS, Yahoo, and Comcast. The Blocklist API detonates links, follows redirect chains, and scans each hop to surface blocklists that affect delivery. Intelligence APIs support verification, engagement prediction, and appending contact details such as names, companies, addresses, and demographics.
The platform is aimed at enterprise senders, email marketers, SaaS platforms, e-commerce, financial services, and media and publishing organizations. It offers a free tier and a free compliance scan, with no credit card required. Deliverability monitoring is priced per host, while API access uses a shared credit system for verification, intelligence, and blocklist calls; purchased credits remain valid for 12 months.
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