K-9 Mail

Communication
3.2
K-9 Mail
K-9 MailK-9 MailK-9 MailK-9 MailK-9 MailK-9 MailK-9 MailK-9 MailK-9 Mail

Installs

5,000,000+

Price

Free

Developers

Mozilla Thunderbird

Content Rating

Everyone

Android Version

5.0

Version

13.0

K-9 Mail APP Download

K-9 Mail is an open source email client designed for Android devices, providing a comprehensive solution for users looking to manage multiple accounts effortlessly. With its support for virtually every email provider, it caters to a wide audience, ensuring you stay connected with ease.

Features
One of the standout features of K-9 Mail is its Unified Inbox, allowing users to view messages from multiple accounts in one place. Furthermore, it's built with your privacy in mind, as it does not track your data and only communicates with your email provider. The app also supports automatic background synchronization and push notifications, local and server-side search capabilities, and even OpenPGP email encryption for enhanced security.

This email client is especially appealing for those who are privacy-conscious, thanks to its commitment to being privacy-friendly. Users can enhance their email security by integrating the OpenKeychain: Easy PGP app for easy encryption and decryption of emails.

Despite its robust features, K-9 Mail has faced criticism regarding its user interface and performance in recent updates, with many users reporting crashes and notification issues. It remains a community-developed project under the Thunderbird umbrella, inviting contributions from new developers and designers looking to enhance the app further.

Conclusion
K-9 Mail is a commendable option for anyone in search of a reliable and secure email client. With a wealth of features and a supportive community, it's a great choice for privacy-centric users. However, potential users should weigh the reported issues against its strengths before making the switch.

User Reviews from Google Play Store

B. Voss

B. Voss

Mar 1, 2026
(1)

With every update they destroy the app more and more.

Version: 16.1

Nima Parandian

Nima Parandian

Feb 28, 2026
(5)

⭐⭐⭐⭐⭐

Version: 16.1

Tushar Thakor

Tushar Thakor

Feb 28, 2026
(5)

must have. for multiple accounts

Version: 16.1

Constantin Runge (Uroc327)

Constantin Runge (Uroc327)

Feb 27, 2026
(1)

I used to prefer K9 due to the nice, compact, no-nonsense view, which allows to work with a large number of mails conveniently. With the current UI redesign, there's too much overly bold font, spacing and too large font in general. Now it's just annoyingly much scrolling and tapping and swiping to see and accomplish anything meaningful.

Version: 16.1

Developer Response

Thanks for the feedback, and we're sorry the recent work feels like it making the app more complicated and more work. This is something we want to improve, as we do want the app to stay easy to use, including for users with multiple accounts.

Charlotte “Ni-dra” Nicholls

Charlotte “Ni-dra” Nicholls

Feb 26, 2026
(1)

Latest updates broke this app's ability to ever connect to any servers. It simply doesn't work, I just get an infinite reload icon. Mail boxes work fine on Thunderbird on Windows.

Version: 16.1

Developer Response

Thanks for letting us know about this, and this is definitely not what should be happening! If you open.a question at Settings > Get Help we'd like to do more detailed troubleshooting, along with our community. Thanks!

Pros

Open source and privacy-focused
Supports multiple email accounts
Unified Inbox feature
No tracking or ads

Cons

Recent updates led to UI and performance issues
Frequent crashes reported
Unreliable notifications
K-9 Mail

K-9 Mail

Communication
3.2

Available Versions

K-9 Mail

Version 13.0

12 MB

APK
Download
Download onGoogle Play

Comments