There are several reasons to hire a Koa.js developer: Koa.js is a Node.js web framework that provides a number of features to make web development simpler, such as providing middleware functions and error handling. Koa.js developers are typically well-versed in JavaScript and Node.js, which makes them able to develop web applications quickly and efficiently. In addition, Koa.js developers often have experience with other popular web frameworks such as Express.js, which can be helpful in understanding your application's needs.