81 tools · 29 open-source · 52 SaaS
The best email clients & servers. Ranked by real activity.
The top-ranked open-source email client or server on Enlisted is docker-mailserver (19k GitHub stars), followed by Mailspring and Mail-in-a-Box. Among SaaS products, other tools on Enlisted are most often compared with Fastmail, Gmail and Microsoft Outlook.
Enlisted lists 81 email clients & servers: 29 open source and 52 SaaS. 28 of the open-source ones can be self-hosted on your own server or computer. The most common open-source licences here are GPL-3.0 (8 tools), AGPL-3.0 (4) and MIT (3). The open-source ones are most often listed as alternatives to Gmail, Microsoft Outlook and Zoho Mail.
Last updated October 3, 2026 · ranked by GitHub stars, growth and recent commits
The top 48 of 81 email clients & servers
docker-mailserver
Email Clients & Servers
Production-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus,
MITvs Gmail★ 19k
Mailspring
Email Clients & Servers
:love_letter: A beautiful, fast and fully open source mail client for Mac, Windows and Lin
GPL-3.0vs Microsoft Outlook★ 18k
Mail-in-a-Box
Email Clients & Servers
Mail-in-a-Box helps individuals take back control of their email by defining a one-click,
CC0-1.0vs Gmail★ 15k
Stalwart
Email Clients & Servers
All-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMA
OSSvs Google Workspace★ 15k
Thunderbird for Android
Email Clients & Servers
Thunderbird for Android – Open Source Email App for Android (fka K-9 Mail)
Apache-2.0vs Gmail★ 14k
Mailcow
Email Clients & Servers
mailcow: dockerized - 🐮 + 🐋 = 💕
GPL-3.0vs Google Workspace★ 14k
Inbox Zero
Email Clients & Servers
The world's best AI personal assistant for email. Open source app to help you reach inbox
OSSvs Superhuman★ 12k
Tuta
Email Clients & Servers
Tuta is an email service with a strong focus on security and privacy that lets you encrypt
GPL-3.0vs Gmail★ 8k
Mailu
Email Clients & Servers
Insular email distribution - mail server as Docker images
OSSvs Gmail★ 7.5k
Roundcube
Email Clients & Servers
The Roundcube Webmail suite
GPL-3.0vs Gmail★ 7.2k
SimpleLogin
Email Clients & Servers
The SimpleLogin back-end and web app
AGPL-3.0vs ImprovMX★ 7kMaddy
Email Clients & Servers
✉️ Composable all-in-one mail server.
GPL-3.0vs Gmail★ 6.1kMox
Email Clients & Servers
modern full-featured open source secure mail server for low-maintenance self-hosted email
MITvs Gmail★ 5.9k
Proton
Email Clients & Servers
Monorepo hosting the proton web clients
GPL-3.0vs Gmail★ 5.6k
FairEmail
Email Clients & Servers
Fully featured, open source, privacy friendly email app for Android
GPL-3.0vs Gmail★ 4.7k
Modoboa
Email Clients & Servers
Mail hosting made simple
ISCvs Google Workspace★ 3.5k
AliasVault
Password Management
Privacy-first password manager with built-in email aliasing. Fully encrypted and self-host
AGPL-3.0vs NordPass★ 3.1k
BillionMail
Email Marketing
BillionMail gives you open-source MailServer, NewsLetter, Email Marketing — fully self-ho
AGPL-3.0vs Mailchimp★ 16k
Rspamd
Email Clients & Servers
Rapid spam filtering system.
OSSvs Mimecast★ 2.5k
SOGo
Email Clients & Servers
SOGo is a very fast and scalable modern collaboration suite (groupware). It offers calenda
GPL-2.0vs Google Workspace★ 2.2k
addy.io
Email Clients & Servers
Anonymous email forwarding
AGPL-3.0vs ImprovMX★ 4.9k
Mail0
Email Clients & Servers
Experience email the way you want with Mail0 – the first open source email app that puts y
MITvs Superhuman★ 11k
Forward Email
Email Clients & Servers
Privacy-focused encrypted email for everyone. All-in-one alternative to Gmail + Mailchimp
OSSvs Fastmail★ 1.7k
Proton Mail Bridge
Email Clients & Servers
Proton Mail Bridge application
GPL-3.0★ 1.6k
Dovecot
Email Clients & Servers
Dovecot mail server
OSS★ 1.3k
RustMailer
Email Clients & Servers
A self-hosted Email Middleware for IMAP, SMTP, Gmail API, Graph API — built for developers
OSSvs Nylas★ 508
UnInbox
Email Clients & Servers
Modern email for teams and professionals. A replacement for outdated email technology and
OSSvs HEY★ 1.8k
Thunderbird
Email Clients & Servers
EXPERIMENTAL - copy of comm-central for forking on github
OSSvs Microsoft Outlook★ 195
Mailpile
Email Clients & Servers
A free & open modern, fast email client with user-friendly encryption and privacy features
OSSvs Spark Mail★ 8.8kAgentInbox
Email Clients & Servers
Disposable inboxes for autonomous workflows that receive emails and OTPs and extract magic links
SaaS
AgentTeamEmail
Email Clients & Servers
Gives each AI agent a real mailbox on your own domain
SaaS
AOL Mail
Email Clients & Servers
Free web email service from Yahoo with a large storage allowance
SaaS
Apple Mail
Email Clients & Servers
Built-in Apple email client supporting iCloud, Gmail, Outlook and IMAP accounts
SaaS
Autofile.email
Workflow Automation
Watches your inbox and saves receipts, invoices and PDF attachments to cloud storage, sorted by sender and date
SaaS
AutoPrintEmail
Workflow Automation
Prints emails and attachments automatically from Gmail, Outlook and IMAP accounts
SaaS
autoremind.ai
Email Clients & Servers
Writes and sends escalating follow-up emails from your own Gmail in the original thread until someone replies
SaaS
Axigen
Email Clients & Servers
Email and collaboration server for hosting providers and businesses
SaaS
BlueMail
Email Clients & Servers
Cross-platform email client with unified inboxes and a calendar
SaaS
Boomerang
Email Clients & Servers
Gmail and Outlook add-on for scheduling emails, reminders and tracking
SaaS
bytemailapp.com
Email Clients & Servers
Native email client for macOS
SaaS
Canary Mail
Email Clients & Servers
Secure email client with AI features and end-to-end encryption options
SaaS
ChatTempMail
Email Clients & Servers
Disposable email service with AI summaries, real-time translation and email management
SaaS
Clean Email
Email Clients & Servers
Inbox cleaner that bulk-sorts, unsubscribes and deletes unwanted email
SaaS
Edison Mail
Email Clients & Servers
Email app with unified inbox, smart replies and unsubscribe tools
SaaS
eM Client
Email Clients & Servers
Desktop email client with calendar, tasks and contacts for Windows and Mac
SaaS
Fastmail
Email Clients & Servers
Paid email provider with custom domains, calendars and contacts
SaaS
Gmail
Email Clients & Servers
Google email service with search, filters, labels and spam protection
SaaS
Gmelius
Email Clients & Servers
Shared inbox and workflow tool that runs inside Gmail
SaaS
Email clients & servers: questions
- What is the best open-source email client or server?
- docker-mailserver is the top-ranked open-source email client or server on Enlisted, with 19k GitHub stars. It is followed by Mailspring, Mail-in-a-Box and Stalwart.
- What are the best free email clients & servers?
- The top-ranked open-source email clients & servers with a standard licence are docker-mailserver (MIT), Mailspring (GPL-3.0) and Mail-in-a-Box (CC0-1.0), so their code is free to use. 26 of the 52 SaaS products here have a free plan, including Gmail, Microsoft Outlook and Spark Mail.
- Which email clients & servers can be self-hosted?
- 28 of the 29 open-source email clients & servers on Enlisted can be self-hosted on your own server or computer; the top-ranked are docker-mailserver, Mailspring and Mail-in-a-Box.
- How are these email clients & servers ranked?
- Open-source tools are ordered by a score built from GitHub stars, star growth over the last 30 days and how recently the code changed; 24 of the 29 had new commits or a release in the last 30 days. SaaS products have no public repository, so they get a fixed baseline score. GitHub data is refreshed daily, and nobody can pay to move up.