MCP server for Microsoft Exchange - on-prem, hybrid and online.
Postgate AI exposes Exchange mailboxes as an MCP server: 67 tools over SSE and Streamable HTTP, OAuth 2.0/PKCE, delegated per-user permissions. EWS for on-premises, Microsoft Graph for the cloud - hosted in Germany.
The technology in six points
The MCP standard
Model Context Protocol - the open standard through which AI assistants access external systems. Postgate AI exposes Microsoft Exchange as an MCP server: for Claude, ChatGPT, Gemini and any other MCP-capable client.
Transports: SSE & Streamable HTTP
Both MCP transports are supported - compatible with desktop clients, mobile apps and agent platforms. TLS on every route.
OAuth 2.0 / PKCE
Verified identity instead of trust-based headers: clients authenticate via OAuth 2.0 with PKCE, self-service onboarding via Microsoft sign-in or a one-time code from the portal.
Per-user vault
Exchange credentials are stored RSA-4096-encrypted per user in a vault in Germany. Delegated access with existing Exchange permissions - no service account, no application impersonation.
EWS and Microsoft Graph
On-premises and hybrid via EWS (Exchange Server SE, 2019, 2016), Exchange Online via the Microsoft Graph API - one connection for every Exchange flavor.
67 tools
Mail, calendar, contacts, tasks, folders, attachments (incl. PDF/DOCX/XLSX extraction), threads, global address list, free/busy times and semantic search - the entire mailbox as a toolbox.
One server, three worlds
AI assistants
Claude, ChatGPT, Gemini and any MCP-capable client - desktop and mobile.
Agent platforms
n8n, Microsoft Copilot Studio, Zapier, Make - automations run server-side around the clock, even when no PC is on.
Your own agents
Any MCP-capable runtime can use the tools - from a Python script to a full agent platform.
Frequently asked questions
What is an MCP server for Microsoft Exchange?
A server that makes Exchange mailboxes accessible to AI assistants via the Model Context Protocol (MCP): emails, calendar, contacts and tasks as standardized tools that Claude, ChatGPT or your own agents can call - with the permissions of the respective user.
Does the MCP server work with Exchange on-premises?
Yes - that is the core: connection via EWS for Microsoft Exchange Server SE, 2019 and 2016, plus Exchange Hybrid and Exchange Online via the Microsoft Graph API. As a hosted solution, with no installation on clients.
Can I use the MCP server in n8n or Copilot Studio?
Yes. Via SSE or Streamable HTTP, Postgate AI can be added as a tool source in n8n, Microsoft Copilot Studio, Zapier or Make - agents then work with the mailbox server-side, around the clock.
How do users authenticate?
Clients via OAuth 2.0 with PKCE; the user’s Exchange credentials are stored encrypted in the per-user vault. Every access is delegated, using the existing Exchange permissions of the respective user.
Exchange as an MCP server - testable in minutes.
7 days free with your own mailbox: connect your EWS URL, pair a client, use the tools.