Email Deliverability Data, Native in Your AI Workflow.
The Model Context Protocol (MCP) lets AI assistants like Claude, Cursor, and other MCP-compatible clients call real tools. Postmaster+ ships a hosted MCP that exposes the full deliverability stack — verification, intelligence, monitoring, blocklists, Gmail Postmaster Tools, Outlook SNDS, Validity, and Universal Feedback Loop — and we maintain open-source MCPs for Gmail Postmaster Tools and Outlook SNDS as standalone tools for the community.
The Postmaster+ MCP
One MCP server, every signal that matters for inbox placement. Authenticated users can connect their AI client to Postmaster+ and immediately call tools that span Gmail, Outlook, Validity, the Universal Feedback Loop, blocklists, and our own Email Intelligence engine.
Email Intelligence
Verification, engagement scoring, and contact enrichment in a single tool call.
Deliverability Monitoring
Pull DNS, reputation, authentication, and sender compliance signals on demand.
In-Depth Blocklist Scans
Query only the impactful blocklists that actually affect inbox placement.
Gmail Postmaster Tools
Domain-level Gmail reputation, spam rate, compliance signals, authentication, encryption, and delivery error data.
Outlook SNDS
IP-level Smart Network Data Services metrics for Microsoft inboxes.
Validity & Universal FBL
Tap into Validity data and Universal Feedback Loop signals from one MCP.
Why teams pick the Postmaster+ MCP
Open-Source MCPs We Maintain
Want just one piece of the stack? We open-sourced two focused MCP servers — one for Google's Postmaster Tools v2 API and one for Microsoft's latest SNDS OAuth REST API. Both run locally, both ship an MCPB bundle on their latest release, and both are free to use, fork, and contribute to.
Gmail Postmaster Tools MCP
Google Postmaster Tools v2 API, exposed as MCP
A local MCP server that wraps the latest Gmail Postmaster Tools v2 API so any MCP-compatible AI client can query your domain's Gmail compliance signals, authentication results, encryption, and delivery errors.
Download .mcpb
Outlook SNDS MCP
Microsoft SNDS OAuth REST API, exposed as MCP
A local MCP server for the newest Outlook Smart Network Data Services OAuth REST API — pull per-IP reputation, complaint, and traffic data for Microsoft inboxes directly inside any MCP client.
What is MCP?
The Model Context Protocol is an open standard that lets AI assistants talk to external tools and data sources through a consistent interface. Instead of stitching together one-off integrations, an MCP-compatible client (Claude Desktop, Cursor, Windsurf, and a growing list of others) can connect to any MCP server and instantly use its tools.
For email teams, that means asking your AI assistant questions like "what's my Gmail spam rate this week?" or "verify this list and flag risky addresses" and getting real answers backed by live data — not hallucinations.