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JSON Formatter & Validator

Format, beautify, and validate JSON instantly.

JSON (JavaScript Object Notation) is the most common data interchange format on the web. Developers, data engineers, and API consumers frequently encounter minified or malformed JSON that is difficult to read. Our JSON Formatter & Validator beautifies, minifies, and validates JSON with clear, actionable error messages.

Paste or type your JSON into the editor. Click Format to indent it with 2 or 4 spaces for readability, or click Minify to strip whitespace and reduce file size for API requests and data transfer. The Copy button copies the formatted output to your clipboard in one click.

The validator checks your JSON against the ECMA-404 standard using a native JSON parser. If there is a syntax error, we show you the exact error message and approximate line/column position so you can fix it quickly. Common issues include missing commas, trailing commas, unquoted keys, and single quotes instead of double quotes.

Like all of our tools, your JSON is processed entirely in your browser. No data is sent to our servers, so you can safely format API responses containing secrets, tokens, customer data, or confidential configurations. The tool works offline once the page has loaded.

Frequently Asked Questions

My JSON is valid but shows an error — why?
Make sure you are using valid JSON syntax: property names must be double-quoted, strings must use double quotes (not single), no trailing commas are allowed, and comments are not part of the JSON standard. Tools like JSON5 and HJSON extend JSON but are not standard.
What is the difference between 2-space and 4-space indentation?
Purely readability preference. 2-space indentation is the JavaScript/Node.js convention and makes deeply nested objects fit on screen. 4-space is common in Python and many teams prefer it for visual clarity. Both produce syntactically identical JSON.
Is there a file size limit?
The tool works best with JSON under about 5 MB. Very large files may slow down your browser tab due to text rendering. For files larger than 10 MB, we recommend using a local command-line tool like jq instead.
Can I convert JSON to JavaScript object syntax?
Our current tool formats and validates standard JSON (always with double-quoted keys). Converting to JS object notation (unquoted keys, single quotes, trailing commas) is a planned feature.
Can the formatter sort keys alphabetically?
Not currently, but this is on our roadmap. Sorted keys are useful for comparing two JSON objects semantically. For now, you can use the Diff Checker to compare JSON values.

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