React is a specific library for JavaScript, and as an entry-level React developer, you use your knowledge of JavaScript, CSS, HTML, and other web scripting languages to integrate ReactJS and other JavaScript library functions into front-end applications or websites. Your other responsibilities include working with quality assurance specialists to test your code or build before an application or website goes live with the public. As an entry-level developer, you typically work with a larger team of developers, programmers, and designers, directed by a project manager who works closely with the company or clients to implement your designs.