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K-9 Mail

K-9 Mail is a free, open-source email app for Android. Full-featured email client. It has 14,150 GitHub stars and is released under the Apache-2.0 license, and you can install it from F-Droid and Google Play.

github.com/thunderbird/thunderbird-android (opens in a new tab)

Data as of from the GitHub API and the F-Droid index; description from the project's repository or F-Droid listing. Report an error

Get it on F-Droid (opens in a new tab)Google Play (opens in a new tab)View on GitHub (opens in a new tab)

About K-9 Mail

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. Want to help? K-9 Mail is a community developed project. If you're interested in helping to improve the app, please join us!

Privacy and F-Droid

F-Droid builds K-9 Mail from its published source code and flags anti-features such as ads, tracking or reliance on non-free services.

No anti-features flagged on the latest F-Droid build.

Screenshots

  • K-9 Mail screenshot 1
  • K-9 Mail screenshot 2
  • K-9 Mail screenshot 3

Screenshots from the app's F-Droid listing.

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FAQ

K-9 Mail FAQ

Still curious? Email info@appsgit.com.

Is K-9 Mail free and open source?

Yes. K-9 Mail's source code is public on GitHub under the Apache-2.0 license, which is OSI-approved or FSF-free. F-Droid, which builds it from source, flags no anti-features such as ads or tracking on its latest build.

How do I install K-9 Mail?

You can install K-9 Mail from F-Droid (package com.fsck.k9) and from Google Play; the links are on this page. Its GitHub repository also publishes releases (latest: K9MAIL_24_0).

Is K-9 Mail still maintained?

The repository's most recent commit was on Oct 22, 2026. Its F-Droid listing was last updated on Oct 18, 2026. appsgit only lists apps whose repository had a commit in the last six months.