JSON Formatter & Validator

Format, minify and validate JSON instantly. Pretty print with 2-space, 4-space or tab indentation, spot errors with line numbers, and copy clean output in one click.

Indent:

Paste messy or minified JSON and get clean, indented output instantly. The formatter validates your JSON in real time, highlights syntax errors with line numbers, and lets you switch between pretty-printed and minified views with one click.

When to Use the JSON Formatter & Validator

Use the JSON formatter when debugging API responses, cleaning up config files, validating webhook payloads, or preparing JSON for documentation. It is also useful for comparing two JSON structures side by side after formatting both.

Tips

  • Use 2-space indentation for compact output and 4-space for maximum readability.
  • Minify JSON before sending it over APIs to reduce payload size by 30-60%.
  • If validation fails, check for trailing commas, single quotes, or unquoted keys — the three most common JSON errors.
  • Copy the formatted output and paste it into your code editor to keep clean formatting.

Frequently Asked Questions

Is my JSON data sent to a server? ▾

No. All formatting, minification and validation happens entirely in your browser using the built-in JSON.parse and JSON.stringify methods. Your data never leaves your machine.

What counts as valid JSON? ▾

Valid JSON must use double-quoted strings for keys and values, cannot have trailing commas, and supports objects, arrays, strings, numbers, booleans and null. Our validator shows the exact line and position of any syntax error.

Can I format large JSON files? ▾

Yes. The formatter handles files up to several megabytes comfortably since it runs natively in your browser engine. For extremely large files (50MB+), a desktop tool may be faster.

What is the difference between format and minify? ▾

Format (pretty print) adds indentation and line breaks so JSON is easy to read. Minify removes all whitespace to produce the smallest possible output — ideal for APIs and storage.

Does it fix invalid JSON automatically? ▾

No. The tool validates and reports errors with exact line numbers so you can fix them yourself. Auto-fixing would risk silently changing your data structure.

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