This paper introduced the concept of transpilers (source-to-source translators). What transpilers actually do is converting, i.e. translating a programming language into another programming language. This paper focuses on the Javascript transpilers which target Javascript programming language. Several transpilers have been introduced through the paper with most focus on Babel, CoffeeScript and TypeScript. Before that necessary introduction to ECMAScript and it's versions throughout years was presented. Babel is a Javascript transpiler that can translate the latest version of Javascript into the code that is run on every internet browser. This paper described its features, presented code examples, examples of new syntax coming to ES17 and built-in features necessary for support React JSX additions and Flow Annotation. Papers also described CoffeeScript transpiler, a transpiler that enables the use of many Javascript features by adding syntactic sugar to Javascript. The CoffeeScripta syntax, which has no semicolons and curly braces, is depicted and described. CoffeeScript has similar syntax to Python and Ruby. For these reasons, writing of the CoffeeScript code is quick and painless, and it’s also easy to read and maintain. Some CoffeeScripta keywords are described, how CoffeeScript works with specific operators and strict mode. It can be concluded that the CoffeeScript code after translating becomes equally successful or in some cases even more effective Javascript code. Finally, TypeScript transpiler is also described. Presented are the essential features of TypeScript, which are optional static types in the code, as well as concept and realization of classes and interfaces. The biggest advantage of TypeScript, beside the introduction of objectoriented language features in Javascript is the fact it provides a richer development environment where it is much easier to perceive precise errors when writing code. Writing a program in TypeScript is fast and due to its great compiler, the number of errors remains at minimum.