Most of the time I’m working on K-9 Mail. But occasionally I find the time to create a small app.

K-9 Mail

This is what got me into Android development. K-9 Mail is a powerful email client for Android that is currently used by more than 2 million people. And it’s probably one of the oldest open source Android apps.

To date over 140 people have contributed to the app. But there is still a lot of work to be done. And we welcome every helping hand. Head over to the project page on GitHub to learn more.


You can download K-9 Mail from Google Play. The source code is available on GitHub.

Attach Contact

This app allows you to attach contacts to your emails just like any other file. Android’s Contacts app itself only supports this functionality via the Share action. But that can’t be used e.g. when replying to an email.

Attach Contact is available on Google Play.

K-9 Mail DashClock Extension

This is an extension for the popular DashClock Widget to display the number of unread messages in K-9 Mail.


You can download K-9 Mail DashClock Extension from Google Play. The source code is available on GitHub.

K-9 Mail for SmartWatch

If you own a Sony SmartWatch 2 and use K-9 Mail on your phone you might be interested in this app. It displays notifications for new mails on the smartwatch.


You can download K-9 Mail for SmartWatch from Google Play. The source code is available on GitHub.


I created a couple of small libraries that aim to make developers’ lives easier. They have all been released under an open source licence and are available on Github.


ckChangeLog provides an easy way to display a change log in your Android app.
It uses a simple XML file as data source and supports translations using Android’s resource system.



SafeContentResolver is a replacement for Android’s ContentResolver that protects against the Surreptitious Sharing attack.


EmailIntentBuilder is an Android library for the creation of a android.intent.action.SENDTO Intent with a mailto: URI. Apps can use this Intent to tell the user’s email app to compose a new message with some fields prepopulated.

Example usage:

        .subject("Message from an app")
        .body("Some text here")