IMAP / POP accounts

Use the IMAP + SMTP flow for any provider other than Gmail. That currently includes Outlook / Microsoft 365, Yahoo, iCloud, Fastmail, self-hosted mail, legacy corporate Exchange, and anything else that speaks IMAP. Outlook and Yahoo each have a dedicated guide with prefilled server settings (Outlook, Yahoo); this page covers generic IMAP.

What you need

Field	Where to find it
IMAP host	Your provider’s help docs (e.g. imap.fastmail.com)
IMAP port	Usually 993 (TLS) or 143 (STARTTLS)
IMAP username	Usually your full email address
IMAP password	Your mailbox password or an app-specific password
SMTP host	e.g. smtp.fastmail.com
SMTP port	465 (TLS) or 587 (STARTTLS / submission)
SMTP username	Usually the same as IMAP
SMTP password	Usually the same as IMAP

Provider quick reference

Provider	IMAP	SMTP
iCloud	imap.mail.me.com:993	smtp.mail.me.com:587 (app-specific password required)
Fastmail	imap.fastmail.com:993	smtp.fastmail.com:465 (app-specific password recommended)
Proton Bridge	127.0.0.1:1143	127.0.0.1:1025 (only works if Bridge is running; not useful for a hosted client)
Zoho	imappro.zoho.com:993	smtp.zoho.com:465
Generic	see provider docs	see provider docs

App-specific passwords

Most providers require an app-specific password when you have 2FA enabled (everyone should have 2FA enabled). Generate one from your provider’s security settings, then paste it into SuperMail’s IMAP/SMTP form.

Note

Your password is stored encrypted in our secrets manager, not in the main database. We only decrypt it in memory at sync time.

Sync model

We use IMAP IDLE for providers that support it (most do), falling back to polling every 60 seconds otherwise. New mail appears in SuperMail within a few seconds on IDLE-compatible servers.

Flags and folders

• IMAP \Seen, \Flagged, \Deleted, \Answered flags round-trip in both directions.
• IMAP folders map to SuperMail folders directly.
• IMAP keywords (custom flags) map to SuperMail tags.

Troubleshooting

• “IMAP login failed” - double-check the app-specific password (no trailing spaces).
• “Connection refused” - verify the host + port. Some corporate firewalls block port 993.
• “Certificate mismatch” - your server’s TLS cert doesn’t match the hostname. Don’t disable TLS; contact your provider.

See Troubleshooting for more general sync issues.