The thesis goal was to create a website allowing users to trade products online. The application’s target user is everyone who has internet access. The theoretical background provides React.js, Node.js, MongoDB, JavaScript, Express.js, and REST API definitions and functions. The theories from the theoretical background part will provide solid knowledge for the implementation part. The thesis’s implementation part is about planning and coding for the website, including server-side and client-side implementation. Also, the website will be demonstrated by images in this part. The result of this thesis is a functional website that allows users to buy/ trade products online. Keywords: web development, full-stack, MERN Stack, React