Free JSON Formatter & Beautifier
Paste your JSON below to instantly format, validate and minify it. Syntax errors are highlighted with line/column references. Your last JSON is auto-saved locally.
About the JSON Formatter
This free JSON formatter and beautifier runs entirely in your browser using JavaScript's built-in JSON.parse() and JSON.stringify() APIs. Paste any raw, minified or malformed JSON and instantly get a clean, indented, human-readable result. The tool also doubles as a JSON validator — if your input contains syntax errors, the exact line and column number are reported.
Common developer use cases include formatting API responses, debugging webhook payloads, prettifying config files, and comparing JSON structure before committing to version control.
How to Format JSON Online
Paste Your JSON
Copy your minified, raw, or API response JSON into the Input field.
Click Format
Hit "Format / Beautify". The output pane shows indented, readable JSON instantly.
Adjust Indent
Choose 2 spaces, 4 spaces, or tabs from the indent selector to match your project style.
Copy or Minify
Copy the formatted output to clipboard, or hit "Minify" to collapse it back to a single line.
Key Features
- Format JSON with 2-space, 4-space or tab indentation
- Minify JSON to a single compact line
- Syntax error detection with line and column reference
- Auto-saves last input to localStorage (up to 50 KB)
- Copy output to clipboard in one click
- Sample JSON for quick demonstration
- 100% private — no data leaves your browser
Frequently Asked Questions
JSON formatting (beautifying) adds consistent indentation and line breaks to compact JSON, making it easier for humans to read and debug. Minifying does the reverse — removes whitespace to reduce file size for production use.
Yes. All formatting happens inside your browser using JavaScript. Your JSON is never sent to any server. The auto-save feature stores data only in your browser's localStorage.
The formatter handles JSON files up to several megabytes without issue. Very large files (10+ MB) may take a second or two on slower devices but will complete without any server round-trip.
Common issues include trailing commas (not allowed in standard JSON), single quotes instead of double quotes, unquoted keys, or comments. JavaScript object notation is not valid JSON. Use the error message to locate and fix the exact character position.