K-9 Mail
In-app purchases
3.7star
100K reviews
5M+
Downloads
Rated for 3+
info
About this app
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.
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.
Updated on
Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection
Data is encrypted in transit
Data can’t be deleted
Ratings and reviews
3.7
94.7K reviews
Jared Reid
- Flag inappropriate
18 July 2025
the app is okay, though I'm not a fan of the way the unified inbox is sorted, like it isn't the top heading in a folder with multiple inboxes. it's not intuitive. and, what about unified spam, trash, and draft folders? good UI and it works well enough without ads on your face.
19 people found this review helpful
Mozilla Thunderbird
18 July 2025
Thanks for your review! We're responding to feedback like yours, and our upcoming changes to the account drawer will also include a better experience for the Unified Inbox and other unified folders. You can read more and see screenshots in the Juny Mobile Progress Report at blog.thunderbird.net!
Philip Taylor
- Flag inappropriate
25 November 2025
This used to be an excellent app, however today I received an unauthorised update. The easy to navigate account selector has been changed to something very inferior, unintuitive and not very helpful. Now I am faced with having to click a drop down to select the account instead of simply selecting it from the list. Please revert it to the perfectly functional interface we have come to know and love, not some inferior attempt to look hip and trendy. Or at least make it a configuration choice.
3 people found this review helpful
Will S
- Flag inappropriate
- Show review history
26 November 2025
I've finally gotten over my hatred for the new interface, ok. But now, it shuts down EVERY time I open it and I then have to reopen it to see my mail. What is up with that! Last update was supposed to fix that. If it doesn't get fixed soon, my frustration is going to lead me to find another email app, or just use the AOL Webmail option I've been trying to avoid. thx UPDATE - after applying the 14.0 update, K-9 is STILL ending abruptly each time I select a notification. Very very disappointing.
1 person found this review helpful
Mozilla Thunderbird
24 November 2025
Thanks for letting us know about these crashes and we're so sorry they kept happening! The recent 14.0 update had some fixes for certain crashes, and we hope this has improved your performance. If it hasn't, please open a question at Settings > Get Help so we can troubleshoot this in more detail.
What's new
- 'Auto-fit messages' setting did not persist
- Edge-to-edge move/copy regressed with 3-button nav
- Swiping message left/right could abort prematurely
- Outlook SMTP failed authentication for some accounts
- Gmail folder prefixes appeared after refreshing folder list
- Quiet time preferences were ignored
- Thunderbird could crash after deleting an account
- Edge-to-edge move/copy regressed with 3-button nav
- Swiping message left/right could abort prematurely
- Outlook SMTP failed authentication for some accounts
- Gmail folder prefixes appeared after refreshing folder list
- Quiet time preferences were ignored
- Thunderbird could crash after deleting an account
App support
About the developer
MZLA TECHNOLOGIES CORPORATION
mobile-appstore-admin@thunderbird.net
149 New Montgomery St Fl 4
San Francisco, CA 94105
United States
+1 650-910-8704
