K-9 Mail

Name: K-9 Mail
Availability: InStock
Rating: 3.84403657913208 (99906 reviews)
Author: Mozilla Thunderbird

Mozilla Thunderbird

In-app purchases

3.8

99.9K reviews

5M+

Downloads

Rated for 3+

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

Jul 9, 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

3.8

94.7K reviews

Pavel Goloviy

December 18, 2023

Very good professionally made mail application! Good minimalist and convenient UI, love the vibes of Mozilla Thunderbird. Works flawlessly with my two email accounts. I do miss PIN code lock feature when you have to enter code after launching the application. I had several occasions when I had to pass over my unlocked phone to another person for a short while and my email is a sensitive content that I would like to have extra privacy protection for.

11 people found this review helpful

Sara Gartner

July 17, 2025

Professional design, aliases supported, missing signature formatting though I was looking for an Android alternative to Outlook as it does not support email aliases. So grateful that K-9 Mail does. I was worried about the design and functionalities, but these are well carried out. One star less though for the missing signature formatting. I'd need to format the text and add an image for business emails. Hoping for that feature to be added soon! 🙏

Jared Reid

July 18, 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.

Mozilla Thunderbird

July 18, 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!