Open Source Everything

Email

Reading and sending email.

5open alternatives 2do the whole job

Open alternatives5

Open-source apps that replace Gmail and Microsoft Outlook

Tuta screenshot
8kActiveWindows · Mac · Linux · Android · iPhone · In your browserGPL-3.0App

Tuta Mail is an email service with built-in end-to-end encryption, with open-source apps for web, desktop and phones. It is for people who want private email and are fine using Tuta's own hosted service, which cannot be self-hosted.

App · GitHub · Moves you to Tuta's own email service; other providers not supported
Thunderbird screenshot
Not on GitHubActiveWindows · Mac · Linux · AndroidVerifiedMPL-2.0App

Thunderbird is a free, open-source email app for Windows, macOS and Linux that also includes calendars and contacts, with an Android app for email. It suits people who want to manage their email and calendars in one desktop program without relying on a big tech company.

App · Own website · Desktop and Android apps; no iPhone app
Mailspring screenshot
18kActiveWindows · Mac · LinuxGPL-3.0Replaces partlyApp

Mailspring is a desktop email app for Windows, Mac and Linux that lets you read and send email from one place. It is aimed at people who want a faster, lighter alternative to web-based or heavy mail clients.

App · GitHub · Desktop only; some features paid
Roundcube screenshot
7.2kActiveIn your browserGPL-3.0Replaces partlyRuns on your own server

Roundcube is a webmail program you install on your own server so you can read and send email in a web browser. It is meant for people or organizations who want to run their own email web interface.

Runs on your own server · GitHub · Inbox screen only; needs your own mail server
FairEmail screenshot
4.7kActiveAndroidGPL-3.0Replaces partlyApp

FairEmail is an email app for Android phones that works with most email providers, including Gmail and Outlook. It is aimed at people who want a privacy-focused way to read and send email.

App · GitHub · Android only

What's missing

What people still miss here, and wish existed. Upvote what matters to you.

Before you build

Planning something for email? See what exists first, so you can reuse parts or explain what's different. Paste this into any AI assistant:

Read the list of open-source alternatives at https://opensourceeverything.org/data/groups/email.json. Compare it with my project or idea below. Tell me which projects overlap, what I could reuse instead of rewriting, and what mine does that none of them do. My project or idea:
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Fix the list itself

A project or closed app missing from this list, or a mistake on it? These open a short form on GitHub, and a mod reviews it. To say what a project can't do, use What's missing.

About this page

Replaces fully means it does the main job of these apps; Replaces partly means it covers some of it.

Licenses: every project here uses an open-source license (what each one means). Open core means some parts are paid or under another license.

GitHub stars are shown for reference. They measure popularity, not whether it replaces anything.

Verified means r/TrueOpenSource mods checked it: open-source license, maintained, and it really does the job.

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