Connect Fastmail to Claude and ChatGPT
Yes — Claude and ChatGPT can both read, search and reply to your Fastmail through Mailopoly, which is listed in the Claude Connectors Directory and is an approved app in the ChatGPT app directory. Connect Fastmail to Mailopoly with a Fastmail app password, add Mailopoly in Claude or ChatGPT, and ask. The whole setup takes about a minute. Fastmail requires a dedicated app password for every mail app — your normal or two-step password won't work — and Basic-plan accounts can't use IMAP at all.
Before you start
- A Mailopoly account — 7-day free trial, no credit card.
- Fastmail requires a dedicated app password for every mail app — your normal or two-step password won't work — and Basic-plan accounts can't use IMAP at all.
- Claude on any plan, including Free, or ChatGPT with apps enabled.
Connect Fastmail to Claude or ChatGPT in three steps
1Connect Fastmail to Mailopoly
- Start a Mailopoly account at mailopoly.com/sign-up — 7-day free trial, no credit card.
- In Fastmail, open Settings → Privacy & Security → Connected apps & API tokens and choose New app password. Fastmail's app password help has the current steps.
- Choose access Mail (IMAP/SMTP), name it Mailopoly, and copy the password Fastmail shows you.
- In Mailopoly choose Add email account, enter your Fastmail address and paste the app password. Mailopoly fills in the server settings for you.
Provider help: Fastmail help: app passwords ↗
2Add Mailopoly to Claude or ChatGPT
This part is the same whatever you connected in step 1. Mailopoly is listed in both directories, so it's a search and a tap — no endpoint URL to paste.
Claude
- Open Settings → Connectors on claude.ai or in the Claude app — or choose Add connectors from the + menu in any chat.
- Search the directory for Mailopoly and choose Connect.
- Sign in with your Mailopoly account when prompted, then choose what Claude is allowed to do. Reading, making changes and sending are separate permissions.
- Back in the chat, make sure the Mailopoly connector is switched on, then ask.
One listing covers Claude.ai, Claude Desktop, Claude mobile, Claude Code and Cowork, and it works on every Claude plan, including Free. In Claude Code you can also run claude mcp add --transport http mailopoly https://fastapi.prod.aws.mailopoly.com/mcp-server/ and then /mcp to sign in.
ChatGPT
- Open the Apps directory in ChatGPT — from the + menu in any chat, or Settings → Apps & Connectors.
- Search for Mailopoly and choose Connect.
- Sign in with your Mailopoly account when prompted, then choose what ChatGPT is allowed to do. Reading, making changes and sending are separate permissions.
- In any chat, type
@Mailopolyand ask.
Mailopoly is an approved app in the ChatGPT app directory, so there's no developer mode and no endpoint URL to paste. Once connected it's available in every ChatGPT conversation on the web and in the mobile apps.
Using something else? Claude Code, Cowork, Codex and any client that supports remote MCP servers connect the same way — the Mailopoly MCP page has the endpoint and per-client steps.
3Ask about your Fastmail
Whatever you've connected to Mailopoly is what your assistant can reach. Some things people ask on day one:
- What's new in my Fastmail Cleanbox since yesterday?
- Find the domain renewal invoice in my Fastmail and tell me when it's due.
- Reply to the last email from the co-working space from my Fastmail address.
Fastmail server settings
Mailopoly fills these in for you when you enter your address. They're here in case you need to check them or your provider uses something unusual.
| IMAP server | imap.fastmail.com |
|---|---|
| Port | 993 |
| Security | SSL/TLS |
| Username | Your full email address |
| Password | Fastmail app password with Mail (IMAP/SMTP) access |
What Claude and ChatGPT can do with Fastmail through Mailopoly
- Search Fastmail — and every other account you own — in one question. By sender, date, topic, or the half-remembered phrase somewhere in the body.
- Read your Cleanbox, not your whole inbox. Mailopoly sorts Fastmail as it arrives: personal and important mail in Cleanbox, promotions and newsletters in Other. Ask for either.
- Summarise a thread, a day or a week. "What did the school send this week?" comes back as an answer, not a list of links.
- Reply from your Fastmail address, in your voice. Save a draft to Mailopoly for review, or send — sending is a separate permission and a confirm-first action.
- Schedule a send for later, and cancel it if you change your mind.
- Pull out invoices, events and deliveries. Amounts and due dates, calendar invitations, parcel tracking — extracted on arrival and added to My Day.
- Find an attachment. Every attachment from Fastmail lands in PolyBox, so "find the PDF the accountant sent" just works.
- Unsubscribe, snooze, file and mark read from the chat, on whichever account the mail belongs to.
Reading, making changes and sending are separate permissions you grant when you connect, and you can revoke an assistant at any time from Settings → Security in the Mailopoly app. More on the security page.
What goes wrong with Fastmail, and the fix
- Your normal Fastmail password won't work, and neither will your two-step verification code. Only an app password is accepted by mail apps.
- Basic-plan accounts can't use IMAP. Fastmail limits IMAP to its Standard and Professional plans, so a Basic mailbox can't be connected.
- Choose the right access level when creating the app password — it needs Mail (IMAP/SMTP), not read-only or calendar access.
7-day free trial, no credit card. Connect Fastmail in about a minute.
Frequently asked questions
Other connect guides
Email providers
- Gmail
- Outlook
- Yahoo Mail
- iCloud Mail
- AOL Mail
- Comcast Email
- Zoho Mail
- Yandex Mail
- GMX
- Fastmail
- Any IMAP Mailbox
