Run TypeScript Online — Free Online TypeScript Compiler

TypeScript adds static types to JavaScript, catching whole classes of bugs before your code runs. But setting up a local TypeScript project — Node, npm, a compiler config — is a lot of friction just to try the language. With GoCode you can run TypeScript online, free, straight in the browser.

Your first TypeScript program

Select TypeScript in the GoCode IDE and paste this in:

const greet = (name: string): string => "Hello, " + name + "!";
console.log(greet("World"));

Hit Run and you'll see Hello, World! in the output. The type annotation : string tells the compiler what to expect — try passing a number and watch it complain.

How it runs under the hood

GoCode strips the types and executes your code on Node, so you get the fast, forgiving "just run it" experience while still writing typed code. That's ideal for learning: you see results immediately, and you can layer in interfaces, generics and unions as you go.

What to try next

• Define an interface for an object and use it to type a function parameter.
• Write a generic function like identity<T>(x: T): T.
• Read a number from input and print its square.

No downloads, no build step — open the IDE and start typing.