Hawk-eye is a technology used in tennis for determining if the ball is in or out. This line-calling system uses multiple camera angles to trace the tennis ball's trajectory. Hawk-Eye uses six or more computer-linked television cameras situated around the court.

An electronic line judge is a device used in tennis to automatically detect where a ball has landed on the court. Attempts to revolutionize tennis officiating and the judging of calls in the sport began in the early 1970s and has resulted in the design, development and prototyping of several computerized, electronic line-judge devices.

Since 2017, WTT has used Hawk-Eye Live, an automated line-calling system created by the same company that handles tennis’ electronic challenge replays. Instead of relying on line judges to make calls, Hawk-Eye’s cameras and computers do the job themselves, complete with human-sounding “out” calls.