K-9 Mail
Communication
5 Million+ installs
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- CategoryCommunication
- PlatformAndroid
- DeveloperMozilla Thunderbird
- In-app PurchasesYes
- Installs5 Million+
- Updated2026-10-06
- Size9 M
- Version24.0
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Editor's Review
Developed by Mozilla Thunderbird, K-9 Mail is a communication app available on Google Play. The developer sums it up as: "K-9 Mail is a 100% open source, privacy focused email client for Android." With 5 Million+ installs on Google Play, it holds an average rating of 3.0 from 99.7K user ratings. The latest version (24.0) was released on 2026-10-06, so the app is still being actively updated. Good to know: it offers optional in-app purchases and needs about 9 MB of storage.
How To Use?
supports multiple accounts
privacy-friendly (no tracking whatsoever, only connects to your email provider)
automatic background synchronization or push notifications
local and server-side search
OpenPGP email encryption (PGP/MIME)
Google Play
Description
K-9 Mail is an open source email client that works with basically every email provider.
Features
* supports multiple accounts
* Unified Inbox
* privacy-friendly (no tracking whatsoever, only connects to your email provider)
* automatic background synchronization or push notifications
* local and server-side search
* OpenPGP email encryption (PGP/MIME)
Install the app "OpenKeychain: Easy PGP" to encrypt/decrypt your emails using OpenPGP.
Support
If you're having trouble with K-9 Mail, ask for help in our support forum at https://forum.k9mail.app
Want to help?
K-9 Mail is now part of the Thunderbird family and remains a community developed project. If you're interested in helping to improve the app, please join us! You can find our bug tracker, source code, and wiki at https://github.com/thunderbird/thunderbird-android
We're always happy to welcome new developers, designers, documenters, translators, bug triagers and friends.
Screenshots
3.0
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