The Sketch plugin works with Sketch 3.8 and newer and is open-source on GitHub.
Download the latest release.
Unzip the file.
Open the WakaTime.sketchplugin file to install the plugin.
Enter your API key
, then click OK.
Use Sketch like you normally do and your time will be tracked for you automatically.
Visit https://wakatime.com/dashboard to see your logged time.