Use this JSON formatter when your payload is valid but hard to read. Paste minified or compact JSON and turn it into clean, indented output for debugging, code review, documentation, or inspection.
A formatter is for readability, not repair. If the JSON is invalid, the right next step is to validate the payload and fix the syntax error before trying to pretty-print it again.
This is useful for API responses, exported config files, CMS payloads, webhook bodies, and any data structure that is technically valid but unreadable as one long line.
Everything runs locally in your browser, so internal payloads and production responses stay on your machine.
If formatting fails, switch to the JSON Validator. If the payload is ready for deployment and you want the smallest possible output, use the JSON Minifier.
How to format JSON
- Paste valid JSON or a minified JSON payload into the input box.
- Run the formatter to pretty-print the structure with consistent indentation.
- Review the formatted output, copy it, or continue debugging with the validator if parsing fails.
JSON Transformation
{"id":1,"name":"test"}{
"id": 1,
"name": "test"
}Indentation Conventions: 2 Spaces, 4 Spaces, or Tabs
Indentation style in JSON is not specified by the format itself, but strong conventions exist across language ecosystems. Most JavaScript and TypeScript projects use 2-space indentation, following the patterns set by Node.js core and popular style guides like Airbnb and StandardJS. Python projects tend to use 4 spaces, matching PEP 8 conventions that carry over into JSON configuration files. Java and C# ecosystems also lean toward 4 spaces.
Tabs offer a different trade-off. They separate indentation semantics from visual width, letting each developer configure their editor to display tabs at their preferred width. However, tabs in JSON files can cause issues with strict parsers and create inconsistent alignment when mixed with spaces.
The practical choice should match your project's existing conventions. If your .editorconfig or prettier configuration specifies 2 spaces for JavaScript files, your JSON files should follow the same rule. Consistency within a project matters more than any universal standard. This tool defaults to 2-space indentation but supports customization for teams with different preferences.
Why Formatted JSON Matters for Code Review
Minified JSON stored in version-controlled files creates serious problems for code review. When an entire JSON object exists on a single line, any change to one value produces a diff that highlights the entire line as modified. Reviewers cannot see what actually changed without manually comparing the before and after states character by character.
Formatted JSON with consistent indentation produces meaningful diffs. Changing a single value shows exactly one line modified in the pull request. Adding a new key shows a clean insertion. Removing a field shows a clear deletion. These atomic diffs make code review faster and reduce the chance of unrelated changes slipping through unnoticed.
This matters most for configuration files, package.json dependencies, translation files, and API fixture data. These files change frequently and are reviewed by team members who need to understand the intent of each modification. Committing formatted JSON is a small investment that pays off every time someone reviews a change.
Some teams minify JSON for production deployment while keeping it formatted in source control. Build pipelines can handle this transformation automatically, giving you the best of both worlds: readable diffs in review and compact payloads in production.