JSON Formatter & Validator — Format, Validate, and Convert JSON Online

Paste JSON to format, validate, minify, or convert instantly. Tree view, diff compare, auto-fix for errors. Zero ads, 100% client-side — your data never leaves the browser.

Formatted output will appear here...

Frequently Asked Questions

Is my JSON data safe?

All processing happens entirely in your browser using JavaScript. No data is sent to any server, stored, or logged. Your JSON never leaves your device.

Can this tool fix invalid JSON?

Yes. The auto-fix feature repairs common errors: trailing commas, single quotes, unquoted keys, comments, and missing commas. Click 'Try to Fix' when JSON is invalid.

What's the maximum JSON size?

There's no hard limit. The tool handles files up to 10MB+ in most browsers. Formatting a 5MB file typically takes under a second.

What JSON spec does the validator use?

It uses the native JSON.parse() function, which follows ECMA-404 / RFC 8259 — the same parser used by all modern browsers and JavaScript runtimes.

Can I convert JSON to CSV or YAML?

Yes. Use the JSON→CSV, CSV→JSON, and JSON→YAML tabs. For CSV, you can configure the delimiter. Nested objects are flattened with dot notation.

What makes this different from jsonformatter.org?

Zero ads, instant formatting as you paste, tree view, JSON diff/compare, auto-fix for errors, and converters (CSV, YAML, TypeScript) — all in one tool.

Does the diff compare semantically?

Yes. It parses both JSON documents and compares data structures, ignoring formatting differences. This is more useful than a plain text diff.

What are common JSON errors?

Trailing commas, single quotes instead of double quotes, unquoted keys, comments (not allowed in JSON), and missing closing brackets. The auto-fix feature handles most of these.

Related Tools

Related Tools