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JSON Editor & Formatter

Paste your JSON data below to validate, format (pretty-print), or minify it instantly. This tool runs entirely in your browser — your data never leaves your device.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is based on a subset of the JavaScript programming language and is used extensively in web APIs, configuration files, and data storage.

A valid JSON document must have either an object ({}) or an array ([]) as its root element. Objects contain key-value pairs separated by commas, where keys must be strings enclosed in double quotes. Values can be strings, numbers, booleans (true/false),null, objects, or arrays.

How to Use This Tool

  1. Paste your JSON data into the input area above.
  2. Click Format to pretty-print with proper indentation.
  3. Click Minify to remove all whitespace for compact output.
  4. Click Validate to check if your JSON is syntactically correct.
  5. Click Copy to copy the result to your clipboard.

Common JSON Mistakes

  • Trailing commas — JSON does not allow trailing commas after the last item in an object or array.
  • Single quotes — JSON requires double quotes for strings, not single quotes.
  • Unquoted keys — All object keys must be wrapped in double quotes.
  • Comments — Standard JSON does not support comments (// or /* */).

Frequently Asked Questions

Is my data private?

Yes. This tool processes everything locally in your browser. No data is sent to any server. You can verify by checking the Network tab in your browser's developer tools — you'll see zero outgoing requests when you format or validate.

What is the maximum JSON size this tool can handle?

This tool can handle JSON files up to several megabytes comfortably. For very large files (100MB+), consider using a desktop JSON editor like VS Code with the JSON extension.

Does this tool support JSON5 or JSONC?

No, this tool validates against the strict JSON specification (RFC 8259). JSON5 features like comments, trailing commas, and unquoted keys will be reported as errors.