AI for Microsoft Exchange On-Premises - no cloud required.
Postgate AI connects your self-hosted Exchange Server to Claude, ChatGPT, Gemini and other AI assistants: server-side, set up once, for all employees - each with their existing Exchange permissions.
Why on-premises Exchange has been left without AI
Copilot doesn't reach you
Microsoft 365 Copilot requires a mailbox in Exchange Online. If you run Microsoft Exchange on-premises, there is no native AI from Microsoft - so far only an interest survey.
EWS stays available on-prem
The 2026 EWS retirement only affects Exchange Online. Exchange Server SE, 2019 and 2016 keep EWS (Exchange Web Services) - exactly the interface Postgate AI connects through.
Workarounds don't scale
Copying emails into chat tools, or improvised setups on individual workstations: per user, dependent on a running PC, without central control. Company-wide, you need a server-side solution.
From Exchange on-prem to an AI mailbox in three steps
No agent on clients, no changes to Exchange, no new permission model: Postgate AI connects via EWS and uses the permissions that already apply today. Hybrid environments and Exchange Online are covered by the same solution via the Microsoft Graph API.
- 01
Connect your EWS URL
Your Exchange Server must be reachable via HTTPS - at least for our server IP. Autodiscover suggests the URL automatically in the portal.
- 02
Users pair their mailbox
Each employee stores their own Exchange credentials once (delegated access, stored encrypted). No service account, no impersonation.
- 03
Connect your AI assistant
Claude, ChatGPT, Gemini or any other MCP-capable client - in the chat interface you already use, on desktop and mobile. The Outlook add-in is optional.
Frequently asked questions
Does this work with Exchange 2016 and 2019?
Yes. Microsoft Exchange Server Subscription Edition (SE), Exchange 2019 and Exchange 2016 are connected via EWS - including versions whose Microsoft support ended in October 2025. Exchange Hybrid and Exchange Online run via the Microsoft Graph API.
Can I connect ChatGPT to my Exchange Server?
Yes. Postgate AI exposes your mailboxes as an MCP server; ChatGPT, Claude, Gemini and any other MCP-capable assistant access it - each user only their own mailbox.
Does my Exchange have to be exposed to the internet?
The EWS endpoint must be reachable via HTTPS, at least for the IP address of our server in Germany. Many on-prem environments already meet this (OWA/ActiveSync); otherwise a firewall rule for a single IP is enough.
Can it run entirely without cloud AI?
Yes. If you prefer, Postgate AI works with a locally hosted model (e.g. via Ollama) - grounding and AI processing then stay entirely in Germany or on your premises.
Your Exchange stays. The AI joins it.
Try Postgate AI free for 7 days with your own Exchange Server - no credit card, ends automatically.