Like or unlike a checkin

https://api.foursquare.com/v2/checkins/CHECKIN_ID/like
Allows the acting user to like or unlike a checkin.
HTTP MethodPOST
Requires Acting UserYes (learn more)
Modes supportedswarm (learn more)
Parameters
All parameters are optional, unless otherwise indicated.
CHECKIN_IDXXX123YYYYrequired The checkin to like or unlike.
set1If 1, like this checkin. If 0 unlike (un-do a previous like) it. Default value is 1.
Response fields
likesUpdated count and groups of users who like this checkin. Groups generally include friends and others (indicating the relationship to the acting user), but are subject to change.