In developed countries, fitness is playing a more and more critical role in human society. However, while a fitness coach cost 65-70 dollar per hour on average, people cannot afford fitness coach in the United States. We are convinced that there is a great market opportunity here, and we have developed an APP called HiFit! that enables beginners and advanced bodybuilders to search for each other. In this way, beginners can find bodybuilders who are willing to work out together and provide professional instruction during breaks in the gym, and bodybuilders can also earn extra money in the gym without influencing their regular training. Besides, this APP provides an excellent opportunity for males and females to hang out together very naturally.