Linux native application
Other options are nice, but we expect a well-integrated Linux app.
The TimeCamp app places itself in the status panel area of the desktop. It offers a hybrid between a native app and a web-based one. For example, several functions open a page in your browser. However, it does provide some advantages of a native app as the usage reports contain detailed records of your actual desktop use, showing which apps and browser windows you were using at different times, something that wouldn’t be possible from a purely web-based tracker.