TypeScript Playground

Write, run, and share code snippets — no setup required.

index.ts

Alice
30

Output

Click Run to see the output here.

declare function require(m: string): any;

const fs = require('fs');
const [name, ageStr]: string[] = fs
    .readFileSync(0, "utf8")
    .trim()
    .split('\n');
const age: number = parseInt(ageStr, 10);
console.log(`Hello, ${name}! You are ${age} years old.`);

Run TypeScript online in your browser

A free online TypeScript playground and compiler. Write TS in your browser, hit Run, and tsgo (the native Go-powered TypeScript compiler) emits JavaScript that Node 24 executes in seconds. No tsc, no ts-node, no tsconfig.json to set up first.

tsgo emits .js from your .ts and Node 24 runs the result, so you get full type-checking without the memory overhead of a transpiler on every execution. @types/node is pre-installed for Node API typings — useful for testing generics, exploring advanced type-level features, or prepping for a TS interview without leaving the page.

What makes this TypeScript playground useful

Instant TypeScript execution — tsgo compiles your .ts files and Node 24 runs them in seconds, with full type-checking.
Full TypeScript syntax highlighting, type-aware autocompletion, and tsgo diagnostics, powered by the same editor engine as VS Code.
Stdin input is supported. Lines feed process.stdin, so typed readline interfaces and async stdin iterators behave the same as running ts-node script.ts locally. No tsc, ts-node, or tsconfig.json to scaffold on your end.
TypeScript 5.3 with tsgo (the native Go-powered TS compiler), ts-node, and @types/node — full type-checking plus ES2022 runtime support.

What you can build in the TypeScript playground

Interfaces, generics, union and literal types, and type guards. Write typed TS, watch tsgo emit clean .js, and run it on Node 24.
Advanced types: mapped types, conditional types, template literal types, and utility types (Pick, Omit, Record), validated by the compiler.
Quick TypeScript experiments: try a new type pattern, confirm a narrowing rule, test a generic constraint, or see how tsgo reports a type error.

Online TypeScript playground FAQ

Is the online TypeScript playground free?

Yes, the TypeScript playground is free to use. No sign-up, no tsc install, and no tsconfig.json to scaffold — open the page and let tsgo compile for you.

Do I need to install tsc or Node to run TypeScript online?

No install needed. You don't need the tsc compiler, ts-node, or a tsconfig.json. tsgo (the native Go-powered TypeScript compiler) emits JS and runs it on Node 24.

Does the TypeScript playground work on mobile and Chromebooks?

Yes. The TypeScript playground runs in any modern browser, on desktop, tablet or mobile. Useful for testing TS snippets from a Chromebook or iPad without installing Node or tsc.

Does the TypeScript playground support stdin?

Yes. After tsgo compiles your .ts and Node 24 executes it, lines you type into the stdin box go to process.stdin. Typed readline interfaces, process.stdin async iterators, and anything typed against @types/node's NodeJS.ReadStream all behave the same as running your script locally.

How do I learn TypeScript after trying the playground?

Edit the sample TypeScript, press Run, and iterate. When you want something more structured, Coddy's interactive TypeScript course covers types, generics, interfaces, and advanced type-level programming.