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ToolsNest

JSON formatter and validator

Paste JSON to pretty-print it, minify it or check it for syntax errors. Errors point to the line and column where parsing failed.

JSON is parsed with the browser's built-in JSON.parse, which never executes code. Nothing is sent to ToolsNest servers.

How to use the JSON Formatter & Validator

  1. 1Paste JSON or load the sample.
  2. 2Select Format, Minify or Validate.
  3. 3Copy the output.

Supported formats and limits

  • Strict JSON only: no comments, trailing commas or single quotes.
  • Indentation: 2 spaces, 4 spaces or tabs.
  • Very large inputs (several MB) may be slow on older devices.

Common uses

  • Reading a minified API response.
  • Finding the stray comma breaking a config file.
  • Minifying JSON before embedding it.

Frequently asked questions

Why are comments rejected?

Standard JSON does not allow comments. Remove them or use a JSON5-aware tool.

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