JSON Formatter

How to format, validate and compact JSON

1. Paste JSON using double-quoted keys and strings.
2. Choose Format JSON for two-space indentation, or Compact to remove formatting whitespace.
3. Check the validation message and download formatted.json if needed.

Example

Paste {"active":true,"items":[1,2]} and choose Format JSON to make the nested structure easier to read. Choose Compact to return it to a single line.

Supported options and limitations

Accepts JSON syntax, not JavaScript objects, comments or trailing commas. Parsing and rewriting can change number precision beyond JavaScript safe integers; duplicate keys keep the final value. Very large inputs can slow your browser. Syntax validation does not validate a schema.

Common questions

Why does my JSON fail validation?

Check for trailing commas, missing brackets, unescaped quotes and single-quoted strings. The error message comes from the browser parser.

Is my JSON sent to a server?

Formatting, validation and downloads run locally in your browser.

Can I validate required fields?

Use JSON Schema Validator for field rules, or JSON Compare to inspect differences between payloads.