What Is Postmaster+?
Postmaster+ is an all-in-one email intelligence and deliverability platform designed for enterprise senders, email marketers, SaaS platforms, and developers. It combines email verification, engagement scoring, data enrichment, deliverability monitoring, and blocklist detection into a single, unified platform.
Why Postmaster+ Exists
Email deliverability is harder than ever. With Google, Yahoo, and Microsoft tightening sender requirements in 2024 and beyond, businesses need more than a simple email verifier. They need a platform that monitors every aspect of their sender reputation — from DNS authentication to blocklist status to mailbox provider feedback.
Most email tools solve one piece of the puzzle. Postmaster+ solves them all. Instead of juggling multiple vendors for email verification, deliverability monitoring, and blocklist scanning, you get everything in one platform with a single API key and a unified credit system.
Three Products, One Platform
Email Intelligence API
Go beyond basic email validation. The Email Intelligence API combines three powerful capabilities into a single API call:
Email Verification
Real-time validation checks syntax, domain MX records, and mailbox existence. Catch invalid, disposable, role-based, and catch-all email addresses before they damage your sender reputation.
Engagement Scoring
Predict email engagement with historical activity data and behavioral signals. Know whether an email address is actively used before you send — reducing complaints and improving open rates.
Data Enrichment
Append postal addresses, demographics, and real-world contact information from email addresses. Enrich your CRM data without third-party append vendors.
Deliverability Monitoring
Track everything that affects your inbox placement in one unified dashboard. Postmaster+ monitors your sender infrastructure continuously:
DNS & Authentication
Continuous SPF, DKIM, DMARC, TLS, and IP rDNS monitoring with instant alerts when configurations change or fail.
MBP Reputation Data
Gmail Postmaster Tools, Microsoft SNDS, Yahoo, and Comcast reputation data aggregated in one place.
Complaint Rate Monitoring
Track spam complaint rates across mailbox providers with customizable thresholds and real-time alerts.
Blocklist Monitoring
Domain and IP blocklist monitoring focused only on lists that actually impact delivery — no noise from irrelevant lists.
Blocklist API
The industry's deepest blocklist detection. Unlike surface-level blocklist checkers, the Postmaster+ Blocklist API detonates every link, follows every redirect, and scans each hop in the redirect chain.
Link Detonation
Every URL is opened and fully analyzed — not just DNS-checked — to detect malicious content and hidden blocklist entries.
Redirect Following
Scans every hop in redirect chains. If a redirect lands on a blocklisted domain, Postmaster+ catches it — even if the original URL looks clean.
Impactful Lists Only
Only checks blocklists known to affect inbox placement at major mailbox providers. No pointless alerts from irrelevant lists.
Simple, Transparent Pricing
Postmaster+ uses a straightforward pricing model. Deliverability Monitoring is $7 per host per month. Email Intelligence and Blocklist API calls use a shared credit system starting at $10 for 1,000 credits, with volume discounts down to $0.005 per credit at scale.
Credits are valid for 12 months from purchase. There's a free tier to get started, and no credit card is required to sign up.
Who Uses Postmaster+?
Enterprise Senders
High-volume senders who need continuous deliverability monitoring, DNS compliance tracking, and real-time blocklist alerts to protect their sender reputation.
Email Marketers
Marketing teams who need to clean email lists, validate subscriber data, and monitor campaign deliverability across Gmail, Outlook, Yahoo, and more.
SaaS Platforms
Product teams integrating email verification at signup to prevent fake accounts, reduce bounce rates, and maintain data quality.
Developers
Engineers who need a well-documented REST API with comprehensive email intelligence, blocklist scanning, and deliverability data endpoints.
How Postmaster+ Is Different
All-in-one platform
Email verification, engagement scoring, data enrichment, deliverability monitoring, and blocklist detection — no need to piece together multiple vendors.
Deepest blocklist detection
Link detonation and redirect following find blocklists that surface-level checks miss entirely.
Only impactful blocklists
We only monitor blocklists known to affect delivery at major mailbox providers. Other tools check hundreds of irrelevant lists and flood you with noise.
Unified credit system
One credit system for all API calls. Buy credits once and use them for verification, enrichment, or blocklist scanning.
Built for deliverability professionals
Aggregated MBP reputation data, DNS monitoring, complaint rate tracking, and sender compliance scoring — not just a verification tool.