JSON Formatter & Validator

JSON arrives minified more often than not — one endless line from an API response or a log export that no human can skim. This formatter parses it with your browser’s own strict JSON engine and re-prints it with clean indentation, so structure, nesting and values are visible at a glance.

Three actions cover the daily jobs: Format beautifies with your chosen indentation (2 spaces, 4 spaces or tabs); Minify strips all insignificant whitespace for the smallest valid payload; Validate checks syntax and reports the browser’s exact error message and position without touching the text.

Because parsing uses the built-in engine, validation is authoritative: if this tool says the JSON is valid, every standards-compliant parser will accept it. And since everything runs locally, it is safe for configs containing credentials you would never paste into a web service.

• Reading API responses — expand a minified response into something a human can navigate.
• Debugging configs — find the trailing comma or missing quote breaking your app, with the error position spelled out.
• Shrinking payloads — minify hand-edited JSON before embedding it where size matters.
• Code review prep — format JSON fixtures consistently before committing.
• Learning the data — reveal the nesting of an unfamiliar structure before writing code against it.

• Strict JSON only: comments, trailing commas, single quotes and unquoted keys are invalid by specification and will be reported as errors — they belong to JSON5 or JavaScript, not JSON.
• Formatting changes whitespace only; key order and values are preserved, and no schema validation is performed.
• Extremely large files (tens of megabytes) are limited by browser memory rather than by this tool.