FourSquare is using API calls that are currently undocumented, yet seem quite interesting if you're integrating with it. Specifically, Documentation on oking a venue has been left out. Like, dislike and their undo counterparts are documented.
Here are the calls needed to rate a FourSquare venue:
Endpoint: https://developer.foursquare.com/docs/venues/like
| Param | Type | Description |