K-9 Mail
In-app purchases
star
99.7K reviews
Rated for 3+
info
5M+
Downloads
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.
K-9 Mail is a 100% open source, privacy focused email client for Android
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 partiesLearn more about how developers declare sharing
- No data collectedLearn more about how developers declare collection
- Data is encrypted in transit
- Data can’t be deleted
Ratings and reviews
94.5K reviews
Boris Riazhskikh
- Flag inappropriate
4 January 2026
Thousands of thanks to developers who made this free alternative to commercial apps with tons of ads. K-9 has very convenient design, and it is quickly running. If you don't receive notifications or app doesn't fetch emails in the background, the reason may be in permissions: you have to switch off battery optimisation for the app, lock it in recently used apps, etc. Ask GPT, it will help. I had to spend some time setting it up, but it is worth it.
7 people found this review helpful
Dan Lapetina
- Flag inappropriate
11 September 2026
K-9 Mail is an excellent email application. Transitioning from a Samsung device to a Google Pixel and initially relying on Gmail was a significant adjustment. While there is nothing inherently wrong with Gmail, it contains far too many convoluted features that do not suit my requirements. I explored numerous alternatives, but none offered the straightforward functionality I was seeking. it's free, but I gladly donated.
2 people found this review helpful
Karl Smith
- Flag inappropriate
5 September 2026
after using the app for years and promoting it to family and friends the recent updates have ruined the in my eyes one of the best email apps out there ... it is so unstable since the update it will not look for new emails ... when emails came in it use to notify me ... now I have to manual update the inbox to see what I have been sent . today I cannot get any emails from my account when updating the inbox it pauses ... I log in to my account other ways and I see there's a small stack .
2 people found this review helpful
Mozilla Thunderbird
10 September 2026
We're sorry you're having issues with retrieving your messages and we'd like to troubleshoot it in more detail with help from our community. Can you please go to Settings > Get Help and open a support question with more information [and any helpful logs and screenshots]? Thank you!
What's new
K-9 Mail version 24.0
New:
- Signatures support HTML
- Reply offers Reply or Reply All
Changed:
- Long account names fit in two lines
Fixed:
- Compose selection invisible in light theme
- Status icons unreadable when selecting messages
- Recipient expander failed to collapse after edit
- Camera attachments could crash the app
- Save All saved each attachment with same file content
- HTML signatures could disappear after rotation
- Edit as new used wrong identity for queued mail
New:
- Signatures support HTML
- Reply offers Reply or Reply All
Changed:
- Long account names fit in two lines
Fixed:
- Compose selection invisible in light theme
- Status icons unreadable when selecting messages
- Recipient expander failed to collapse after edit
- Camera attachments could crash the app
- Save All saved each attachment with same file content
- HTML signatures could disappear after rotation
- Edit as new used wrong identity for queued mail
App support
About the developer
MZLA TECHNOLOGIES CORPORATION
mobile-appstore-admin@thunderbird.net
447 Sutter St
San Francisco, CA 94108-4601
United States
+1 650-910-8704
