1.stalwartlabs / stalwart
All-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP, CalDAV, CardDAV, WebDAV).
+328 stars
from 15,297 · score 5.80
Trending repositories
Ranked by Attention Score: stars gained over the last 7 complete days
17 repositories by Attention Score · Oct 27, 2026 – Nov 2, 2026 (UTC)
2.flectar / mail
Built from the ground up for speed. Flectar Mail delivers native performance, instant startup, and as little as 80 MB of RAM.
+109 stars
from 1,616 · score 4.70
3.Foundry376 / Mailspring
:love_letter: A beautiful, fast and fully open source mail client for Mac, Windows and Linux.
+45 stars
from 17,942 · score 3.83
4.docker-mailserver / docker-mailserver
Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running inside a container.
+35 stars
from 19,680 · score 3.58
5.mailcow / mailcow-dockerized
mailcow: dockerized - 🐮 + 🐋 = 💕
+33 stars
from 13,694 · score 3.53
6.cypht-org / cypht
Cypht: Lightweight Open Source webmail aggregator [PHP, JS]. Supports IMAP/SMTP, JMAP and EWS (Exchange Web Services)
+16 stars
from 1,771 · score 2.83
7.rustmailer / bichon
Bichon – A lightweight, high-performance Rust email archiver with WebUI
+15 stars
from 2,047 · score 2.77
8.s1t5 / mail-archiver
Mail-Archiver is a web application for archiving, searching, and exporting emails from multiple accounts. Featuring folder sync, attachment support, mailbox migration and a dashboard.
+10 stars
from 2,225 · score 2.40
9.forwardemail / forwardemail.net
Privacy-focused encrypted email for everyone. All-in-one alternative to Gmail + Mailchimp + Sendgrid.
+8 stars
from 1,691 · score 2.20
10.jstedfast / MailKit
A cross-platform .NET library for IMAP, POP3, and SMTP.
+7 stars
from 6,863 · score 2.08
11.Mailu / Mailu
Insular email distribution - mail server as Docker images
+4 stars
from 7,592 · score 1.61
12.twisted / twisted
Event-driven networking engine written in Python.
+4 stars
from 5,995 · score 1.61
13.dovecot / core
Dovecot mail server
+4 stars
from 1,271 · score 1.61
14.foxcpp / maddy
✉️ Composable all-in-one mail server.
+1 stars
from 6,115 · score 0.69
15.emersion / go-imap
📥 An IMAP library for Go clients and servers
+1 stars
from 2,357 · score 0.69
16.mguessan / davmail
DavMail POP/IMAP/SMTP/CalDAV/CardDAV/LDAP Exchange and Office 365 Gateway - Synced with main subversion repository at
+1 stars
from 773 · score 0.69
17.danzuep / MailKitSimplified
Send and receive emails easily, fluently, with one line of code for each operation.
+1 stars
from 97 · score 0.69