JSON Formatter & Validator
Paste JSON to instantly format, validate, and syntax-highlight it. Minify or beautify with one click. Runs entirely in your browser.
How to Format JSON Online
ToolsPix JSON Formatter lets you pretty-print, validate, and minify JSON directly in your browser using JavaScript's built-in JSON.parse() and JSON.stringify(). There is no software to install, no account to create, and no data sent to any server.
Why format JSON?
- Compact API responses and config files are hard to read — formatting adds indentation and line breaks instantly.
- The validator highlights syntax errors with exact error messages, so you can fix malformed JSON in seconds.
- Minification strips all whitespace, reducing payload size for network transmission and storage.
- Syntax highlighting color-codes keys, strings, numbers, booleans, and nulls for fast visual scanning.
- Choose between 2-space, 4-space, or tab indentation to match your project's code style.
Formatting steps
Paste your JSON into the Input panel on the left — the formatter validates and pretty-prints it immediately. Click Format to apply indentation, Minify to compact it, or Copy output to copy the result to your clipboard. Use the Indent dropdown to switch indentation style at any time.
FAQ
What does JSON formatting do?
JSON formatting (also called "pretty printing" or "beautifying") takes compact or messy JSON and adds consistent indentation and line breaks to make it human-readable. For example, {"a":1,"b":2} becomes a neatly indented multi-line structure that's easy to read and debug.
What does the validator check?
The validator checks whether your JSON is syntactically valid according to the JSON specification. Common errors include missing commas, trailing commas, unquoted keys, single quotes instead of double quotes, and unclosed brackets. The error message will tell you exactly what's wrong.
What is JSON minification?
Minification removes all unnecessary whitespace from JSON, producing the smallest possible string. This is useful when sending JSON over a network (e.g. API responses) where file size matters. Minified JSON is identical in meaning to formatted JSON — just less readable.
Is my JSON data sent to a server?
No. All formatting, validation, and minification happens locally in your browser using JavaScript's built-in JSON.parse() and JSON.stringify(). Your data never leaves your device and nothing is logged or stored.
Can I change the indentation style?
Yes. Use the Indent dropdown to choose between 2 spaces (default), 4 spaces, or a tab character. The output will update immediately when you change the setting.