K-9 Mail

Name: K-9 Mail
Availability: InStock
Rating: 3.3053691387176514 (99956 reviews)
Author: Mozilla Thunderbird

Mozilla Thunderbird

In-app purchases

3.3

100K reviews

5M+

Downloads

Everyone

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

16 Jul 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

3.3

94.7K reviews

Jared Reid

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.

7 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!

Mik Bel

17 June 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.

21 people found this review helpful

Jessica Meyers

4 December 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.

21 people found this review helpful

Mozilla Thunderbird

4 December 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!