6 open-source email apps
Open Source Email Apps for Android & iOS
The most popular open-source email apps for Android on GitHub are Thunderbird, FairEmail and SimpleLogin. appsgit lists 6, 6 of them on F-Droid, each with its license, last commit and store links.
Updated Oct 8, 2026
Open Source Email Apps for Android & iOS
Thunderbird
thunderbird/thunderbird-android
Thunderbird is a 100% open source, privacy focused email app.
OfficialEmail clientsAndroid
FairEmail
M66B/FairEmail
Fully featured email client. Neat, intuitive user interface.
Email clientsAndroid
SimpleLogin
simple-login/Simple-Login-Android
Protect your email inbox with a secure and open source solution by SimpleLogin.
Email clientsAndroidiOS
Infomaniak Mail
Infomaniak/android-kMail
The secure messaging service for your emails.
Email clientsAndroid
addy.io
anonaddy/addy-android
Anonymous Email Forwarding.
Email clientsAndroid
SMS2Email
SMS2Email/SMS2Email
Forwards SMS messages to SMTP (Email) server.
Email clientsAndroid
What are the best open-source email apps?
By GitHub stars, Thunderbird is the most popular (14,068 stars), followed by FairEmail and SimpleLogin. Each page lists the license, the last commit and the F-Droid, Google Play or App Store link when the project publishes one.
Which of these apps work on iPhone?
1 of the 6 open-source email apps listed here run on iOS, including SimpleLogin, and 6 run on Android.
Are these apps on F-Droid?
6 of the 6 are on F-Droid, which builds them from source. 5 of those have no anti-features (such as ads, tracking or a non-free network service) flagged by F-Droid; each app page lists any that are.
How are these open-source email apps chosen?
Apps come from the F-Droid index (apps whose source code is on GitHub), GitHub topics such as android-app, flutter-app, ios-app and jetpack-compose, and a short hand-checked list of official apps that are not on F-Droid. An app is listed only if its license is OSI-approved or FSF-free (F-Droid's license first, then GitHub's), the repository has a README and a commit in the last six months and is not archived, and it has 100+ GitHub stars (F-Droid apps) or 300+ stars (everything else). Libraries, SDKs, templates, samples and demo apps are left out. Source-available apps are never listed.