K-9 Mail

K-9 Mail
Original author(s)Jesse Vincent
Developer(s)MZLA Technologies Corporation, Christian Ketterer
Initial release27 October 2008 (2008-10-27)
Stable release
8.2 / 10 December 2024 (10 December 2024)
Repository
Written inJava, Kotlin
Operating systemAndroid
TypeEmail application
LicenseApache License 2.0
Websitek9mail.app

K-9 Mail is a free and open source email client for Android. It is designed as an alternative to the stock email clients included with the platform; it supports both POP3 and IMAP protocols and supports IMAP IDLE for real-time notifications. The project is named after the Doctor Who character K9.

For end users, K-9 Mail started to transition towards becoming Thunderbird for Android in October 2024.