AI for your Exchange - including On-Premises.
Postgate AI makes your Exchange mailboxes - On-Premises, Hybrid, or Online - accessible to virtually any AI. Runs server-side, set up once, instantly available to every employee. Hosted in Germany.
- Hosted in Germany
- Individual permissions per employee
- Open standard (MCP) - no vendor lock-in
The AI gap for Exchange On-Premises - and how we close it.
The starting point
For mailboxes in the Microsoft cloud, AI solutions exist - Copilot above all. For self-hosted Exchange (On-Premises), there are none. Organizations running On-Prem are cut off from AI assistants like Copilot, ChatGPT, or Claude.
The status quo
Until now, the only options were manual work: copying emails into chat tools, or improvised setups on individual workstations - per user, dependent on a running PC. A product that connects Exchange On-Premises to AI company-wide didn't exist. Until now.
The Postgate AI approach
The only server-side AI connection for Exchange On-Premises: one central MCP server, set up once, instantly available to every employee in the company. Everyone works with their own mailbox, with exactly the permissions they already have in Outlook - right in the familiar chat interface of Claude, ChatGPT, or Gemini, on desktop and mobile. An add-in inside Outlook is available as an optional extra.
Data location & operations
Postgate AI runs on servers in Germany: requests and responses pass through our server between your Exchange and the AI of your choice - like a transparent proxy, with no storage and no logging of content. We do not operate an AI of our own; you decide which model processes your content.
What you can do with it
Meeting times in seconds - no email back-and-forth
Just ask for a time that works for everyone. Postgate AI checks all attendees' calendars, suggests open slots - and sends out the invite if you want.
Reply to Claude…
Your morning briefing - before your computer is even on
A daily summary of your mailbox: what's new, what matters, and who's been waiting days for a reply - with priority and subject line.
Ask anything
Out-of-office replies on the fly - even from your phone
Just say or type what should apply. Postgate AI drafts a polished out-of-office reply and turns it on once you confirm - wherever you are.
Nothing else on the market does this.
Other solutions only work with Exchange Online, are built for a single person, or depend on a shared account. Postgate AI is the only server-side solution for Exchange On-Premises: set up once, for all employees, each with their own permissions.
Exchange On-Prem and cloud
Self-hosted and cloud from a single solution: On-Premises Exchange (EWS), Hybrid, and Microsoft 365 (Graph) - all fully supported.
Individual permissions per employee
Everyone keeps their existing Exchange permissions - unchanged. No service account with access to all mailboxes, no master key.
Around the clock
Runs centrally on our server - at night too, even when your PC is off. For chat and automation.
Open standard (MCP)
No dependency on any single AI vendor. Claude today, ChatGPT tomorrow - you stay free to choose.
Every access is personal and encrypted. No one can see anyone else’s mailbox, and there is no master key. You don’t need to grant new permissions or redesign your permission model: Postgate AI uses the exact Exchange permissions that already apply today.
One central server, operated by us - no installation on any client.
Each customer gets a hardened, dedicated instance. Set up once, it is available to all employees. Full details are on the technical pages.
Central MCP server
One MCP server for Exchange On-Prem and cloud - serving AI chat and automation/agents from a single source, around the clock.
Every Exchange flavor
Exchange Server SE, 2019, and 2016 (On-Premises, EWS), Exchange Hybrid, and Exchange Online (Graph) through one connection.
Delegated, isolated, encrypted
Existing Exchange permissions instead of impersonation, per-user vault, cross-user isolation.
Verified identity
OAuth 2.0 / PKCE, self-service onboarding via Microsoft sign-in. No trust-based header.
Open integration
The MCP standard over SSE and Streamable HTTP - for any MCP-capable client as well as agent platforms like n8n, Microsoft Copilot Studio, Zapier, or Make.
Operations & compliance
Dedicated instance per customer, hosted in Germany, GDPR-compliant, DPA available. Content is neither stored nor logged.
The full mailbox feature set as AI tools.
Mailbox
- Calendar
- Contacts
- Tasks
- Folders
- Search
- Attachments
Agentic layer
- Rules
- Follow-ups
- Approvals
- Out of office
- Briefings
- Memory
- Writing style
Frequently asked questions
Does Copilot work with on-premises Exchange?
No. Microsoft 365 Copilot requires a mailbox in Exchange Online. For self-hosted Exchange Server (on-premises), Microsoft has so far only published an interest survey - no product. Postgate AI closes exactly this gap - available today.
Do our emails leave the company?
Yes, for processing: requests and responses pass through our server in Germany - GDPR-compliant, with a DPA. We operate like a transparent proxy: no storage, no logging of your content. We do not run an AI of our own; you decide which AI model processes your content.
Why do I have to sign a data processing agreement (DPA)?
Because Postgate AI processes data from your mailboxes on your behalf, the GDPR (Art. 28) requires a data processing agreement (DPA) between you and us - it defines, bindingly, what may happen with your data. Signing it is therefore a fixed part of registration and takes just one click; our subprocessors (such as our hosting in Germany) are listed in it.
Does every employee need new permissions?
No. Existing Exchange permissions apply, unchanged. No new permission model, no shared account.
Which Microsoft Exchange versions are supported?
Microsoft Exchange Server Subscription Edition (SE), Exchange 2019, and Exchange 2016 via EWS - including versions whose Microsoft support ended in October 2025. Plus Exchange Hybrid and Exchange Online via the Microsoft Graph API.
Which AI tools work with it?
Claude, ChatGPT, Gemini, and any other MCP-capable client. Plus agent and automation platforms like n8n, Microsoft Copilot Studio, Zapier, and Make - or your own agents.
What is MCP?
The Model Context Protocol: an open standard that lets AI assistants securely access external systems such as your mailbox. Vendor-neutral, with no lock-in to any single provider.
What does the 2026 EWS retirement mean for us?
It only affects Exchange Online. On-premises Exchange keeps EWS - and for cloud mailboxes, Postgate AI uses the Microsoft Graph API anyway.
Want to see Postgate AI in action?
Get in touch - we will show you how Postgate AI fits into your environment.