JSON Formatter & Validator

// beautify, minify and validate JSON — entirely in your browser

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About This JSON Formatter

This free online JSON formatter and validator instantly beautifies, minifies, and validates any JSON. Paste raw JSON to detect syntax errors with clear messages, or click Beautify to pretty-print with proper indentation and syntax highlighting. Works entirely in your browser — no data is sent to any server.

Common uses: Formatting API responses, debugging JSON payloads, validating config files, minifying JSON for production.

Learn more: JSON.stringify vs JSON.parse · How to fix common JSON errors

Frequently Asked Questions

What is JSON?+
JSON (JavaScript Object Notation) is a lightweight, text-based data format used to store and exchange structured data. It represents data as key-value pairs, arrays, strings, numbers, booleans, and null, and it's the de facto format for REST APIs, config files, and NoSQL databases.
Why do I get a JSON syntax error?+
The most common causes are a trailing comma after the last item in an object or array, missing quotes around keys, single quotes instead of double quotes around strings, or an unclosed bracket or brace. This tool highlights exactly where parsing failed so you can pinpoint the issue quickly.
What's the difference between minifying and beautifying JSON?+
Beautifying adds indentation and line breaks so the structure is easy to read while debugging. Minifying strips all unnecessary whitespace to produce the smallest possible payload, which is useful when sending JSON over a network or storing it in a database.
Can JSON contain comments?+
No. The JSON specification does not support comments, and including one will cause a parse error. If you need comments, consider JSON5, JSONC, or YAML instead, then convert to plain JSON before using it in production.
What's the difference between JSON.parse and JSON.stringify?+
JSON.parse converts a JSON string into a JavaScript object you can work with in code, while JSON.stringify converts a JavaScript object back into a JSON string for storage or transmission. Beautify and minify both use stringify; validation uses parse.
Is it safe to paste sensitive JSON into this tool?+
Yes. This formatter runs entirely in your browser using JavaScript's built-in JSON.parse and JSON.stringify functions. Nothing you paste is ever sent to a server, logged, or stored — refresh the page and it's gone.