http://connect.garmin.com/proxy/oauth-service-1.0/
http://connect.garmin.com/proxy/activity-service-1.3/
http://connect.garmin.com/proxy/activity-search-service-1.2/
http://connect.garmin.com/proxy/upload-service-1.1/
http://connect.garmin.com/proxy/goal-service-1.1/
http://connect.garmin.com/proxy/user-service-1.0/
http://connect.garmin.com/proxy/calendar-service-1.0/
http://connect.garmin.com/proxy/device-service-1.1/
http://connect.garmin.com/proxy/course-service-1.0/
http://connect.garmin.com/proxy/workout-service-1.0/
http://connect.garmin.com/proxy/userstats-service/
http://connect.garmin.com/proxy/personalrecord-service/
http://connect.garmin.com/proxy/userprofile-service/
http://connect.garmin.com/proxy/comment-service/
http://connect.garmin.com/proxy/event-service/
http://connect.garmin.com/proxy/activitylist-service/
http://connect.garmin.com/proxy/group-service/
Garmin use single sign-on auth for all services.**before march-2014**
Read this thread in garmin developers forum
and view good source code from cpfair and his project tapiriik
and view some info from garmin code
Do HTTP POST request to https://connect.garmin.com/signin with parameters:For some actions authentication is not needed.view simple usage examplesloginUsernameField password