“Tennis Serve Tracker” is iOS and Android app that measures tennis serve speed using video processing and image recognition technologies. Why is it worth trying it when there are similar apps on market? Because all these apps can be split on 2 categories - first are the ones that do it very, very bad or simply invent measured speed and won’t be mentioned here at all. The others do measure the serve speed, but it’s a lot of manual interactions with setting multiple parameters, like choosing deuce/ad serve type, server height, marking server and ball positions on the standard court image template that has no resemblance to the actual court we see with our eyes. These actions drastically increase an error margin, time and effort required to perform a single serve speed measurement - does it match fast pacing tennis game we all love?