plMail

Self-hosted mail with a calendar beside it. Connect the mailboxes you already have (IMAP, Gmail, Outlook) and read them side by side in one inbox, on a server you own.

plMail is not a mail server: it does not receive mail from the internet or host your domain. It syncs your existing accounts into your own database, so search is fast and your mail stays readable when a provider is not. It is free software under the AGPL-3.0.

Try it, install it

On your phone