Tool Fu
$ toolfu run json-formatter

JSON Formatter & Validator

Free online JSON formatter, validator, and beautifier. Format, validate, and minify JSON instantly in your browser. Adjust indentation, copy the result — no data sent to any server.

all processing runs in your browser
json-formatter
input > paste JSON

Format, Validate, and Beautify JSON Online

This free online JSON formatter lets you format JSON, validate JSON, and beautify JSON output instantly in your browser. Whether you're working with minified API responses or debugging configuration files, this JSON formatting tool adds proper indentation and line breaks so you can quickly understand the structure of your data.

Paste your JSON, choose your indentation (2 spaces, 4 spaces, or tabs), and click format. The JSON validator checks syntax in real time and shows clear error messages for invalid JSON. You can also minify formatted JSON to produce the smallest possible output for production use.

Online JSON Formatter and Validator

Unlike other JSON formatting tools that send your data to a server, this JSON formatter and validator runs entirely in your browser. Your JSON data never leaves your device — making it safe to format sensitive configuration files, API keys, and private data.

When to use this JSON formatter

  • Format JSON from API responses for easier debugging
  • Validate JSON configuration files before deployment
  • Beautify JSON output for documentation and readability
  • Minify JSON payloads to reduce bandwidth and file size
  • Convert between formatted and minified JSON instantly
$ cat FAQ.md
What does a JSON formatter do?▶
A JSON formatter takes raw or minified JSON and reformats it with proper indentation and line breaks, making it easier to read and debug. It can also validate that the JSON is syntactically correct.
Is my data sent to a server?▶
No. All formatting and minification happens entirely in your browser using JavaScript. Your JSON data never leaves your device.
What is the difference between formatting and minifying?▶
Formatting adds indentation and line breaks for readability. Minifying removes all unnecessary whitespace to produce the smallest possible output, which is useful for reducing payload size in APIs and config files.
Can this tool fix invalid JSON?▶
This tool validates and formats valid JSON. If your JSON has syntax errors (missing quotes, trailing commas, etc.), it will show an error message indicating what went wrong. You will need to fix the syntax manually.