Using Beacons and API Tokens
Beacons are services that can be used to interact with Lighthouse. They can be used for various things such as simple scripts, web services, flash/ajax widgets, to desktop applications. They communicate with Lighthouse with a simple REST interface.
The API
To learn more about how the Lighthouse API works, visit the Lighthouse API section
How to get an API Token
Go to the My Profile link in the top right of the page. There you can create a new API token for your account. You can specify the project if you want, but make sure full access is selected.

Some examples
Here are a few examples of existing Beacon uses: The Lighthouse email system and subversion integration.

