K-9 Mail
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K-9 is an open source email client for Android with multi-folder sync, email signatures, Bcc-to-self, return-address configuration, keyboard shortcuts, Exchange Support, message flagging, IMAP deletes, saving attachments, configurable notifications and more.
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K-9 Mail News & Activities
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Recent News
- POX published news article about Thunderbird
Thunderbird updates Android app and plans to release an iOS version by the end of the yearThe Thunderbird team has announced updates for its Android email client, which is set to replace K-...
- POX published news article about Thunderbird
Thunderbird has just released the first stable version for Android after two years of workTwo years after announcing plans to bring Thunderbird to Android by incorporating K-9 Mail, the Thu...
- POX published news article about K-9 Mail
Thunderbird team improves K-9 Mail with Material 3 design and Android 14 enhancementsThe Thunderbird team has released its May progress report on the transition of K-9 Mail, the open-s...
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What is K-9 Mail?
K-9 Mail information
AlternativeTo Categories
Office & Productivity, Security & Privacy, Social & CommunicationsGitHub repository
- 11,745 Stars
- 2,576 Forks
- 794 Open Issues
- Updated Apr 17, 2025
Comments and Reviews
Easy and reliable open source android email app, have been using this as a daily driver for the last couple of years and have no problems.
Works awesomely, until you need a subfolder in your Inbox (some email hosts insist), which K9 will not see at all. Unlike other apps, it seems K9 can only handle files OR subfolders, but not both.
Subfolders work fine for me over IMAP (you need to tell it to rebuild the folder tree once a new one is added). What do you mean by "files"? Are you referring to the storage type? (I think it was one file per mail / one .mbox file with all mail.)
Open source, free and very light on battery
A great email client which just does what it's supposed to.
Good to know: The old UI is far superior in terms of productivity & acessibility - and there's lots of debate bc the devs have different opinions about the UI layout and ignore the users wishes (toolbar on top is the main issue).
If you want to try or use the old UI, the version is 5.600 (fully functional & stable; afaik the new versions have nothing notable v. 5.600 hasnt - maybe webDAV - support is new).
The screenshots display the old & new UI.
It's the best open source Android email client but it's still way worse than the Gmail app.
The search is garbage, you can't edit it after sending the query.
There is no "Always show images from this sender" option.
Nice interface and easy to configure. Animations make the program feels slow so I disabled them. I prefer it over Fairemail
Best email client for Android