TypeScript Formatter Online — Format TS Code

The OpenFormatter TypeScript formatter is a pretty printer — it preserves your token order and only adjusts whitespace and brace layout, so behaviour is identical and the diff is purely additive. It runs entirely in your browser; nothing is uploaded, no account is needed, no rate limits apply.

How to format TypeScript online — 4 steps

1. Paste your TypeScript. Drop TS or TSX into the Input panel — interfaces, type aliases, generics, classes, decorators, async functions. Click Load Sample to try a generic-heavy demo.
2. Click Format. The formatter rewrites brace placement and indentation client-side and emits one statement per line.
3. Review the output. Confirm nested generics are readable, interfaces have one member per line, and decorators sit on their own line above the declaration.
4. Copy the result. Click Copy to paste into your editor, a PR description, a GitHub issue, or a snippet for your team chat.

Side-by-side: dense input vs formatted output

interface User<T extends string>{id:T;name:string;email?:string;}
type Result<T,E=Error>={ok:true;value:T}|{ok:false;error:E};
function fetchUser<T extends string>(id:T):Promise<Result<User<T>>>{return fetch(`/api/user/${id}`).then(r=>r.json()).then(value=>({ok:true,value})).catch(error=>({ok:false,error}));}
class Cache<K,V>{private store=new Map<K,V>();get(k:K):V|undefined{return this.store.get(k);}set(k:K,v:V):void{this.store.set(k,v);}}

interface User<T extends string> {
  id: T;
  name: string;
  email?: string;
}
type Result<T, E = Error> = { ok: true; value: T } | { ok: false; error: E };
function fetchUser<T extends string>(id: T): Promise<Result<User<T>>> {
  return fetch(`/api/user/${id}`).then(r => r.json()).then(value => ({ ok: true, value })).catch(error => ({ ok: false, error }));
}
class Cache<K, V> {
  private store = new Map<K, V>();
  get(k: K): V | undefined {
    return this.store.get(k);
  }
  set(k: K, v: V): void {
    this.store.set(k, v);
  }
}

Common use cases

• check_circleFormat TypeScript before pasting into a Prettier-enforced project so the diff stays small
• check_circleReformat dense generic-heavy TypeScript copied from Stack Overflow or a GitHub issue
• check_circleClean up auto-generated TS from openapi-typescript, graphql-codegen, or zod schemas
• check_circleIndent a decorator-heavy NestJS controller for a code-review screenshot
• check_circleFormat TSX from a React component before pasting into a documentation site
• check_circleReformat TypeScript types extracted from .d.ts ambient declaration files
• check_circleClean up a one-line interface chain pasted from a TypeScript Playground share link
• check_circleBeautify a Zod schema or io-ts codec where the chained .extend().refine() got compacted

TypeScript formatter vs Prettier vs ESLint

A pretty printer is the lightweight option — it preserves token order and only adjusts whitespace, so the diff is small and the output predictable. Prettier goes further: it re-prints the AST, normalises quote style, enforces line length, applies trailing commas, and splits long generic constraints. ESLint with @typescript-eslint is a different tool entirely — it checks style and correctness rules (unused vars, prefer-const, no-explicit-any) and can autofix some, but is not primarily a formatter. Use this tool for a quick one-off reformat; use Prettier for project-wide enforcement; use ESLint for catching bugs and enforcing patterns.