Go! - Start Clock is a free Android app developed by Tollgate 3 AB that serves as a timing tool for various kinds of races such as orienteering, stair climbing, cross country skiing, downhill skiing, rally, and radio-controlled cars. It can also be used as a watch with GPS synchronization. The app offers interval and chasing start, works on various phone and tablet sizes, and has many user settings that can be configured.

The app's basic functionality includes an audible prewarning that beeps 10 seconds before the start, beeps on the seconds before the start (Get Ready beeps atsec), and beeps even more on the start sec. The actual time settings are user-controlled. The app also displays the current time, countdown of seconds until the next start, and time relative to a given zero time point. Furthermore, users can show call-up time, align time with the timing system of the race, or postpone the race and keep the original start times.