JSON Formatter & Validator
Validate, format, or minify JSON locally in your browser with clear syntax feedback.
Paste valid JSON up to 2 MB. The exact input is parsed locally; whitespace inside strings is preserved.
Formatted or minified JSON
Formatted or minified JSON will appear here. Validation results appear above.
What is JSON?
JSON, or JavaScript Object Notation, is a text data format used by APIs, configuration files, logs, and web applications. JSON supports objects, arrays, strings, numbers, booleans, and null values with strict syntax rules.
What does a JSON formatter do?
A JSON formatter parses valid JSON and writes it back with consistent indentation. This makes nested objects and arrays easier to scan, but it does not preserve the original whitespace or layout choices from the input.
What does JSON validation check?
JSON validation checks whether the input can be parsed by the native JSON parser. It rejects JavaScript-only syntax such as comments, single quotes, unquoted property names, trailing commas, undefined, NaN, Infinity, functions, and duplicate commas.
JSON formatting vs minification
Formatting adds whitespace and line breaks so JSON is easier to read. Minification removes unnecessary whitespace outside strings so the same data is more compact. Both actions parse the input first, so invalid JSON is not silently repaired.
Common JSON syntax errors
JSON objects, arrays, and primitive values
Objects and arrays are the most common JSON root values, but strings, numbers, true, false, and null are valid JSON too. This tool supports primitive JSON values and reports the detected root type after successful validation.
Is JSON formatting secure?
JSON formatting is not encryption and does not hide sensitive values. Formatted or minified JSON remains plain text. Avoid pasting production secrets into any online tool unless you trust the environment and understand how it handles data.
How this tool protects privacy
Validation, formatting, and minification happen entirely in your browser with JSON.parse and JSON.stringify. The tool does not upload your JSON, put it in URLs, store it in local storage or cookies, or include it in analytics events.
How to use the JSON Formatter & Validator
Paste JSON into the input area, choose the indentation style for formatted output, then select Validate JSON, Format JSON, or Minify JSON. Copy becomes available only after formatted or minified output exists, and Clear resets the input, output, status, and errors.