If you’ve downloaded TimeThis and cannot get it to talk back and forth with Basecamp (retrieve projects, submit time, etc.), there’s a good possibility that API access has not been enabled for your Basecamp account.
So how do you enable API access? It’s pretty simple, but there’s one very important point to be made up front: only the Basecamp account owner has the capability of making this change. So if you’re not the account owner, pass along these instructions to him or her.
If you are the Basecamp account owner, log in to your account and click the “Account (Upgrade/Billing)” tab in the upper righthand corner (note: it may just say “Account”).
Scroll down the page to the section labeled “Basecamp API“.
Check the box indicating that you’ve read the “API Terms” section of the Basecamp terms of service (after reading them, of course), and then hit the button to enable the Basecamp API for your account.
Voilà—your Basecamp API has been enabled. Once you enter your Basecamp API URL and Key in the Server Settings tab of the TimeThis settings panel (find out how), TimeThis will be able to retrieve projects from and post time to your Basecamp account.