VOLTUTILS

JSON Formatter

Format, prettify, and validate your JSON strings instantly.

100% Local Processing

About the JSON Formatter

Working with minified or unformatted JSON can be a nightmare. Our JSON Formatter prettifies your data with proper indentation making it human-readable. It also serves as a validator, instantly catching syntax errors, missing quotes, or trailing commas.

How to format and validate JSON

  1. Paste minified or indented JSON into the input area.
  2. Read the validation result; if parsing fails, use the error state to inspect the input.
  3. Copy the formatted result for debugging, documentation, or a readable code review.

Examples and worked results

Before and after

Input
{"name":"Ada","roles":["admin","reviewer"]}
Result
{
  "name": "Ada",
  "roles": [
    "admin",
    "reviewer"
  ]
}

Formatting adds whitespace only; it does not change the JSON values.

Formatting versus validation

The tool parses the input as JSON and serializes valid data with indentation. A valid JSON document requires double-quoted property names and strings, matching braces and brackets, and no trailing commas. JavaScript object literals that use single quotes, comments, or undefined values are not automatically valid JSON.

Common use cases

  • Reading API responses that arrived on one line
  • Checking configuration and fixture files before committing them
  • Finding syntax mistakes in copied JSON payloads

Important notes and limitations

  • It validates JSON syntax, not the application-specific schema or required fields.
  • Trailing commas, single quotes, comments, and mismatched delimiters will fail parsing.

Practical tips

  • When an error is hard to spot, reduce the payload to the smallest failing object and add fields back gradually.

Frequently Asked Questions

Does it validate JSON syntax?

Yes, it highlights errors if your string is invalid JSON.

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