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JSON Formatter & Validator

Paste messy JSON and instantly beautify, minify, or validate it. Our free JSON formatter highlights syntax errors with clear messages showing exactly where the problem is. It is an essential daily tool for developers working with APIs, configuration files, and webhooks.

  • Free, no signup
  • Runs in your browser
  • Works on mobile

Output
Formatted JSON will appear here.

How to use the JSON Formatter

  1. Paste your JSON into the input box.
  2. Click Format to pretty-print it with 2 spaces, 4 spaces or tabs. Tick Sort keys to order object keys alphabetically.
  3. Click Minify to strip all whitespace, or Validate to only check the syntax.
  4. If something is wrong, the message shows the line and column of the error plus a hint for common mistakes.
  5. Copy the output or download it as a .json file. Tip: Ctrl+Enter formats from the keyboard.

About this tool

A must-have for developers working with APIs. The validator uses the browser's native JSON parser and shows exactly where syntax errors occur.

Why use itDebugging a 500-line API response by eye is miserable — one missing comma breaks the entire payload. Our formatter pretty-prints JSON into readable, indented structure, pinpoints parse errors with their exact position, and minifies payloads for production use. Because parsing happens locally in your browser, you can safely inspect JSON containing API keys, tokens, or customer data without sending it to a third-party server.

Frequently asked questions

Is my JSON data uploaded?

No. Parsing happens locally in your browser using the native JSON parser — your data never leaves your device, so it is safe for private API responses.

What does Minify do?

It removes all unnecessary whitespace and line breaks, producing the smallest valid JSON string — ideal for reducing API payload sizes and saving bandwidth.

Why is my JSON invalid?

The most common causes are trailing commas, single quotes instead of double quotes, unquoted keys, and stray comments. The error message shows the exact position of the problem so you can fix it fast.

Can it handle very large JSON files?

Yes, within reason — browsers comfortably format files of several megabytes. For extremely large files (tens of megabytes), a dedicated desktop editor will be smoother.