Connect guide

Connect Fastmail to Muse

Updated 29 October 2026

Yes — Muse can read, search and reply to your Fastmail through Mailopoly. Connect Fastmail to Mailopoly with a Fastmail app password, add Mailopoly to Muse as a custom connector, sign in and ask. One connection covers Fastmail and every other account you own. 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.

Start a free trial

7-day free trial, no credit card.

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.
Access to Muse — Meta is rolling it out country by country.

Connect Fastmail to Muse in three steps

1 Connect 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 ↗

2 Add Mailopoly to Muse

This part is the same whatever you connected in step 1.

Add Mailopoly to Muse

These steps are taken from public documentation, and we haven't yet checked each one in Muse ourselves. If a label doesn't match what you see, Muse's own help page, linked below, has the current wording.

Open a chat in Muse — on the web or in the app — and ask it to create a custom connector for a remote MCP server called Mailopoly at `https://fastapi.prod.aws.mailopoly.com/mcp-server/`. Muse walks you through the rest.
Sign in with your Mailopoly account when prompted, then choose what Muse is allowed to do. Reading, making changes and sending are separate permissions.
Back in a chat, ask.

Mailopoly isn't in Muse's connector list, so Muse takes it as a custom connector — the same connection, added with one sentence instead of a tap. Muse connects from Meta's cloud, so there's nothing to install.

Connectors in Muse — Meta Help Center ↗

3 Ask 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 Muse 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 Muse 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.
Muse doesn't offer to create the connector: say exactly what you want — a custom connector for a remote MCP server called Mailopoly at the address above — and that it signs in with OAuth.
Mailopoly isn't in Muse's connector list: add it as a custom connector instead. It's the same connection to your Mailopoly account.