Is my code sent to any server?

No. All formatting runs in your browser using the Prettier library loaded from a CDN. Your code never leaves your device.

What JavaScript syntax is supported?

Prettier supports ES2020+ including arrow functions, async/await, optional chaining, nullish coalescing, destructuring, and template literals.

Why does formatting fail on some code?

Prettier is a strict parser — it requires syntactically valid JavaScript. If your code has syntax errors (missing brackets, unmatched quotes, etc.) it will report a parse error. Fix the errors first, then format.

Can I format TypeScript or JSX?

This tool targets standard JavaScript (ES2020). For TypeScript or JSX, the parser may reject type annotations or JSX tags. Use a TypeScript-aware formatter for those files.

What is the print width setting?

Print width (default 80) is the column at which Prettier tries to wrap long lines. It is a soft limit — Prettier will not break strings or identifiers, but will wrap function arguments and object properties to stay within the limit.

JS Formatter

Paste JavaScript code, choose your indentation style, and get cleanly formatted output instantly — no server, no upload.

Options: Indent: Semicolons Single Quotes Print width:

Input

Output

Click Format to see output

Copied!

Summary

The JS Formatter reformats messy or minified JavaScript into readable, consistently indented code entirely in your browser. It uses the Prettier library to handle modern JavaScript including ES2020+ syntax, arrow functions, template literals, destructuring, and async/await. No code is ever sent to a server — all processing happens locally in your tab.

How it works

Paste or type your JavaScript code into the input panel.
Choose your preferred indentation: 2 spaces, 4 spaces, or tabs.
Toggle the "Semicolons" and "Single Quotes" options to match your style guide.
Click "Format" — the formatted code appears in the output panel instantly.
Copy the result with one click or download it as a .js file.

Use cases

Beautify minified JavaScript files for debugging.
Enforce consistent code style before committing to a repository.
Quickly reformat code pasted from Stack Overflow or documentation.
Inspect third-party scripts to understand their logic.
Format auto-generated JavaScript from build tools or transpilers.
Clean up code snippets before sharing with teammates.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu