ToolSnap
Developer Tool

JSON Formatter & Validator

Paste raw or minified JSON to instantly format, validate, and beautify it. Works offline — nothing leaves your browser.

Indent
Input

Paste JSON above and click Format to prettify it.

Tip: press ⌘ + ↵ to format instantly.

How to use the JSON Formatter

  1. Paste your raw or minified JSON into the Input area above.
  2. Click Format (or press ⌘ ↵) to prettify with your chosen indentation.
  3. Use Minify to collapse it back into a single line — useful for copying into API requests or config files.
  4. Click Copy to copy the output to your clipboard.

Common use cases

  • Debugging API responses. Paste a raw response body to instantly see its structure, keys, and nested objects.
  • Validating config files. Catch missing commas, unclosed brackets, or wrong quotes before they break a build.
  • Preparing data for code review. Format JSON before pasting it into a PR comment or Slack message so teammates can read it.
  • Minifying for production. Strip all whitespace from a JSON payload to reduce bandwidth in network requests.
  • Learning JSON structure. Explore unknown data formats — the indented view makes nesting and object boundaries obvious at a glance.

Limitations

  • Input is capped at 2 MB to keep the browser responsive. For larger files, use a CLI tool like jq.
  • Comments (// …) are not valid JSON and will cause a parse error. Use Diff Checker to strip them manually.
  • Duplicate keys are preserved as-is — the formatter does not deduplicate or sort keys.

Frequently asked questions

What is a JSON formatter?
A JSON formatter (also called a JSON prettifier or beautifier) takes compact or unformatted JSON and adds indentation and line breaks to make it human-readable. It also validates that the JSON is syntactically correct.
Is my JSON data sent to a server?
No. Everything runs locally in your browser using JavaScript. Your data never leaves your device.
What is the difference between Format and Minify?
Format adds indentation and line breaks for readability. Minify removes all unnecessary whitespace to produce the smallest possible JSON — useful for APIs or configuration files where file size matters.
Can I validate JSON with this tool?
Yes. The tool parses your JSON as it formats it. If there is a syntax error, it shows you the exact location and a clear error message.
What indentation size should I use?
2 spaces is the most common convention for JSON. 4 spaces is also widely used. Tab indentation is preferred in some codebases and matches certain linters.

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