JSON Formatter & Validator
Format (pretty-print), minify and validate JSON in your browser. Clear error messages with line numbers. Your data is never uploaded.
About this tool
Paste JSON to pretty-print it with consistent indentation, minify it to a single line, or validate it. If the JSON is invalid, you get a clear error message — often with the line number — so you can fix it quickly.
Parsing uses the browser's native, safe JSON engine. No code is executed and nothing is uploaded, so it is safe for sensitive payloads.
Examples
- Beautify a minified API response with 2-space indentation
- Minify a config file to a single line
- Catch a trailing comma or missing quote with a line number
Frequently asked questions
Is my JSON sent to a server?
No. Formatting and validation happen entirely in your browser using the native JSON parser.
Does it execute or evaluate the JSON?
No. It uses safe JSON parsing only — never eval — so pasting data carries no risk of code execution.
Why does it reject my JSON?
Common causes are trailing commas, single quotes instead of double quotes, or unquoted keys. The error message points to where parsing failed.
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