JSON Formatter & Validator
Format, validate and beautify JSON online. Instant results, no signup required.
About JSON Formatter & Validator
Paste any JSON document and get a properly indented, validated output in milliseconds. All processing happens in your browser — your data never leaves your device. Supports 2-space, 4-space, and tab indentation. Also includes a minifier for compact output, Sort Keys to alphabetize all object keys recursively, Remove Nulls to strip null values, and Flatten to convert nested objects into dot-notation key-value pairs.
All processing happens entirely in your browser using modern web APIs. Nothing is uploaded to our servers — your data stays local and private. Free to use forever.
Common use cases
- Debugging API responses that are returned as minified JSON
- Formatting JSON config files (package.json, tsconfig, .eslintrc) for readability
- Validating JSON before inserting into a database or sending to an API
- Minifying JSON for production to reduce payload size
- Sorting keys alphabetically for easier diffing in code review
- Flattening nested objects to inspect deeply nested values
How it works
Paste your JSON into the input editor. The tool uses the browser's built-in JSON.parse() to validate and parse the input, then JSON.stringify() with your chosen indent setting to produce the formatted output. Sort Keys recursively sorts all object keys. Flatten converts nested structures like { "a": { "b": 1 } } into { "a.b": 1 }. All transformations run client-side with zero network requests.