AI for your Exchange Server On-Premises.
Postgate AI connects your Microsoft Exchange Server - on-premises and hybrid - to Claude, ChatGPT, Gemini, Mistral Vibe, and any MCP-capable AI assistant. Server-side, set up once, instantly available to every employee - chat, agents, and automation with near-complete mailbox control, like Outlook. Managed by us in Germany or self-hosted on your own server.
- Managed in Germany or self-hosted
- 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 a self-hosted Exchange Server (On-Premises - also written on-premise, on-prem, or "local Exchange Server"), there are none. Organizations running On-Prem are cut off from AI assistants like Copilot, ChatGPT, Claude, or Mistral Vibe.
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, Perplexity, or Mistral Vibe, 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. By default we do not store mailbox content. You can switch on an encrypted short-term cache per organization. It deletes after 7 days by default and you can switch it off again in the portal at any time. We do not operate an AI of our own. You decide which model processes your content.
Chat, agents, and any automation - near-complete mailbox control, like Outlook.
AI chat
Your mailbox in natural language: ask, search, write, schedule meetings - in Claude, ChatGPT, Perplexity, or Mistral Vibe, on desktop and mobile.
Autonomous agents
Assistants running around the clock: triage mail, draft replies, flag follow-ups - even when your computer is off.
Any automation
Connect your own workflows and agent platforms via the open MCP standard - automate what you need, with no vendor lock-in.
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
Remembers your out-of-office - before you do
The AI spots the vacation in your calendar with no out-of-office set - and proactively drafts a ready-to-use reply. One tap and it goes live.
On-premises and individual permissions per employee - in one solution.
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.
For self-hosted Exchange
Exchange Server SE, 2019 and 2016, connected via EWS - including hybrid environments. No cloud mailbox required.
Individual permissions per employee
Everyone keeps their existing Exchange permissions - unchanged. No service account with access to all mailboxes, no master key.
Server-side, 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 your Exchange - serving AI chat and automation/agents from a single source, around the clock.
Every on-prem version
Exchange Server SE, 2019, and 2016 via EWS - including hybrid environments.
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 Streamable HTTP - for any MCP-capable client with OAuth support, including Microsoft Copilot Studio and n8n as agent platforms.
Operations & compliance
Dedicated instance per customer, hosted in Germany, GDPR-compliant, DPA available. By default, mailbox content is neither stored nor logged.
Two equal deployment models.
Same feature set - you choose who runs the server.
Managed by us
A hardened, dedicated instance run by us in Germany - set up once, ready immediately. We operate, patch, and monitor the server for you.
See pricing →Self-hosted
Runs as a service directly on your own Exchange server - operations, data and keys stay with you. Price on request.
More on self-hosted →Almost everything you do in Outlook - now via AI.
Mailbox
- Calendar
- Contacts
- Tasks
- Folders
- Search
- Attachments
- Shared mailboxes
- Bulk actions
AI assistance
- 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. More on this on the "Microsoft Copilot & Exchange On-Premises" page.
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. By default we do not store or log mailbox content. If you want to, you can switch on an encrypted short-term cache per organization, which deletes after 7 days by default. 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. Hybrid environments are supported as well.
Can we self-install Postgate AI on our own server?
Yes. Alongside the managed variant, a self-hosted license runs as a service directly on your own Exchange server - operations, data and keys stay with you. Price on request; more on the "Self-hosted" page.
Which AI tools work with it?
Claude, ChatGPT, Perplexity, and Mistral Vibe are fully supported; Gemini via Gemini Enterprise or Google Antigravity; Microsoft Copilot Studio and n8n as agent platforms. Plus any MCP-capable client with OAuth support - including 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 - exactly the interface Postgate AI connects through.
Want to see Postgate AI in action?
Try Postgate AI free for 7 days with your own mailbox - no credit card, ends automatically.