MCP server · Claude & ChatGPT

One gate to every mailbox. It opens only where you say.

Postern Mail connects your AI assistant to all of your mailboxes — private, business, support. Per mailbox you grant the verbs it may use: read, draft, send. The server enforces the grant on every call. The assistant cannot exceed it.

Create account See how it works
  • Gmail, Microsoft 365 / Outlook and IMAP/SMTP
  • Permissions enforced server-side, per call
  • Your credentials never reach the assistant
agent session · 3 mailboxespostern gate
01 mail.search inbox:work "invoice q3" → 4 results 02 mail.read msg_8213 → ok 03 mail.draft reply msg_8213 → draft saved 04 mail.send draft_312 via support@ → denied · send not granted 05 mail.read inbox:private latest 5 → ok
read search draft send delete

Works with your mail

Gmail Microsoft 365 · Outlook IMAP / SMTP

One connection

Every mailbox you own behind a single endpoint. Your assistant reads this morning's mail across all of them in one instruction.

Per-mailbox grants

Read-only on the private inbox. Draft-only on sales. Full send on your own address. Each mailbox carries its own grant.

Enforced server-side

The server re-reads your stored permissions on every call and denies anything not granted. The assistant's request is never the authority.

Credentials stay home

Mail passwords and tokens are stored encrypted and used only server-side. Nothing of them passes the gate.

How it works

Three steps. Then the gate is yours.

01

Connect your mailboxes

Sign in to the admin and connect Gmail, Microsoft 365 / Outlook or any IMAP/SMTP account.

02

Grant the verbs

Per mailbox, switch on exactly what the assistant may do — read, draft, send — and which folders it may see.

03

Add the endpoint

Add one URL to Claude, ChatGPT or any MCP-capable assistant, and start delegating your daily mail.

Permissions

The grant is the contract.

Close a verb and the agent is refused mid-conversation. There is no override flag, no admin bypass, no "just this once". What you granted is what passes — checked on the server, on every single call.

wim@private.example

read draft send

sales@company.example

read draft send

support@company.example

read draft send
mail.send via sales@ → denied · send not granted mail.send via support@ → sent

Install

One URL, both clients.

https://mcp.posternmail.ai
  • 01Copy your endpoint from the admin.
  • 02Add it as an MCP server in Claude or ChatGPT.
  • 03Approve the connection. The grant does the rest.

Pricing

Free while in beta.

Postern Mail is in beta. Access is free for as long as the beta runs. When the product releases, you will be notified in good time — of the release itself and of any charges — before anything is billed.

Create account