Using the TimeWriter API it is possible to import/export the following data:
•Aspects (employees, customers, projects, activities)
•Relations (combinations en authorizations)
•Hour bookings
To connect to the TimeWriter API you need a API key and a User key. Go to Maintenance and settings | Settings | TimeWriter API.
Click on edit to generate the user key and/or copy the keys. If there is no user key yet, click on 
to generate a new user key.
You can find the manual about using the TimeWriter API here: https://timewriter.com/media/webhelpapi.