There is no unified answer to this question. Each software product built with React.js is unique, and so is the cost. So rather than provide you with some specific figures, we want you to pay attention to two crucial factors that have the biggest impact on React.js development services cost. The first one is the project complexity. The more sophisticated functionality you want to implement, the more time the development team will need to build it. Consequently, the higher price will be. The second factor is the geographic location of the React.js development services provider. To be more specific, according to Codementor.io, the average hourly rate of a senior React.js developer in North America will be $121-140. At the same time, when it comes to Western European developers, these figures will be $81-100. Finally, in Eastern Europe, React.js developers will set hourly rates of $61-80.