K-9 Mail

In-app purchases
3.4
99.9K reviews
5M+
Downloads
Content rating
Everyone
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image

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.
Updated on
May 8, 2025

Data safety

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

3.4
94.7K reviews
K
May 31, 2025
New user. So far good experience. Everything looks and functions well. Look forward to utilizing the email. Do not see a way to log out of the app. When composing an email the recipient's address was hidden now it shows up. Do not know how to change. It is synced to use with another email provider only shows their information.
9 people found this review helpful
Did you find this helpful?
Mik Bel
June 17, 2024
It crashed many times during setup. Can't get passed setup. Edited: After numerous attempts I identified the step at which the setup was crashing. After typing the password to log into my email account, making the PW visible would crash the app. Finally, I set it up. Nice app, simple, not many bells and whistles, works well with Google, Microsoft.
20 people found this review helpful
Did you find this helpful?
Jessica Meyers
December 4, 2024
I loved K-9 before this update. But now it's so hard to distinguish between my accounts in the menu. Before, I'd given each one a different profile pic and color, so I always knew which account I was looking at. They also appeared in a set order, so I could navigate easily. Now 4 of my 5 accounts are labeled "GM," and the highlight color is the same for all 5. What?! AND each time I open an account, the list order shifts, so they're never in a predictable order! Wish there were a way to revert.
20 people found this review helpful
Did you find this helpful?
Mozilla Thunderbird
December 4, 2024
Thanks for your feedback and we're sorry for any frustration over account icons and management. Improvements are coming in the 8.2 release to the current account initials. You can also help us test this and other changes in the K-9 Mail Beta. We hope this and future changes improve your experience!

What’s new

- Server field pre-filled in manual account setup
- Add a menu entry to empty the Spam folder
- Update Gmail OAuth client IDs to Thunderbird for Android
- Preserve the <s> tag when sanitizing HTML content
- Messages and star counts in the drawer update instantly
- Hide accounts setting now remembered across restarts
- Restart PushService after app update