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 Review

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

Horst Storkebaum

Horst Storkebaum

Jan 14, 2026
(4)

Would you please give us the option to choose a much shorter poll / sync intervall than the default 15 minutes? Or please help me understand why syncing every, let's say, 2 minutes is not an option?

Version: 15.0

Joseph Keithley

Joseph Keithley

Jan 14, 2026
(1)

Wow. Gotta love it when developers go backwards. Cant swipe to next message. Cant go back to list after open ing message, just hangs. Only the inbox folder shows up in side panel when using unified inbox.

Developer Response

Ugh, we're sorry this is happening, and this definitely not what should be happening with swipe and going back to your message list. Can you please report these bugs at github.com/thunderbird/thunderbird-android/issues for our developers and bug triage team? And we're working on adding more folders to the Unified Account!

Rob

Rob

Jan 13, 2026
(1)

Post 27-11-2025 updates that make selecting an account & a custom folder within it........When is the 'account drawer'(?) going to be fixed so that back to being less annoying to use??....(Like it was pre November 2025)

Version: 14.0

Developer Response

Thanks for the feedback, and we're sorry for any frustration. The account drawer is still in progress, and we're are listening to user feedback to be sure the finished product ensures more usability and a better experience switching between accounts.

David S

David S

Jan 13, 2026
(5)

Easy to use, fast, reliable, no tracking, no ads. What more could you want?

Version: 14.0

महाराजा of भारतं रोबिन मात्यू राजन

महाराजा of भारतं रोबिन मात्यू राजन

Jan 12, 2026
(5)

K-9 Mail is very good. Developers, I want all the features of Desktop Thunderbird in K-9 Mail.

Version: 14.0

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

Comments