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JSON Formatter & Validator

Beautify, minify, sort keys, and validate JSON syntax instantly — 100% client-side in your browser so sensitive API payloads stay private.

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Inspecting JSON Web Tokens or Base64 payloads? Try our JWT Decoder or Base64 Encode / Decode Tool .

How to Format & Validate JSON Online

  1. Paste your raw JSON string into the Input Raw JSON panel or upload a .json file.
  2. Select your preferred indentation (2 Spaces, 4 Spaces, or Tab).
  3. Click Format / Validate to indent and check syntax, Minify JSON to compress whitespace, or Sort Keys (A–Z) to organize properties alphabetically.
  4. Click Copy JSON or Download to save the clean output.

Common JSON Syntax Rules & Fixes

Rule Invalid Example Valid JSON
Double Quotes Only {'name': 'Alice'} {"name": "Alice"}
No Trailing Commas [1, 2, 3,] [1, 2, 3]
Quoted Property Keys {id: 42} {"id": 42}

Frequently Asked Questions

Is my JSON data secure when using this tool?

Yes. Your JSON is parsed and formatted entirely inside your browser's memory using native JavaScript JSON.parse() and JSON.stringify(). Nothing is ever transmitted to a remote server.

How can I fix trailing commas in JSON copied from JavaScript?

JavaScript allows trailing commas in objects and arrays, whereas strict JSON does not. Click the Fix Trailing Commas button to automatically strip extra commas before closing braces and brackets.