Setup Guide
Fastmail IMAP Setup
Connect Fastmail to Mailszen using an IMAP App Password. Fastmail requires App Passwords for all third-party email clients.
Connection Settings
| IMAP Host | imap.fastmail.com |
| Port | 993 |
| Security | SSL/TLS |
| Username | your@fastmail.com |
| Password | App Password (not your Fastmail login password) |
Step-by-step setup
- 1
Create an App Password in Fastmail
Log into Fastmail → Settings → Privacy & Security → App Passwords → New App Password. Name it "Mailszen" and set access to "Mail (IMAP, POP, SMTP)".
- 2
Copy the App Password immediately
Fastmail shows the App Password only once. Copy it now — if you close this dialog, it cannot be retrieved. Generate a new one if needed.
- 3
Connect in Mailszen
Enter your full Fastmail address and the App Password you just copied. Your regular Fastmail login password will not work via IMAP.
Things to know
- *Fastmail requires App Passwords for all third-party apps — your main Fastmail login password will be rejected.
- *Custom domain emails hosted on Fastmail use the same imap.fastmail.com server.
- *Fastmail is one of the most reliable IMAP providers with fast sync and excellent uptime.
Ready to connect Fastmail to Mailszen?
Join the waitlist. Early access members get a free 14-day trial the day we launch.