JSON Formatter & Validator

Format, validate, and minify JSON instantly in your browser. Nothing is uploaded.

Free tool No account

Input

Output

{
  "name": "Cromagnon",
  "tools": 14,
  "free": true,
  "stack": [
    "pdf",
    "csv",
    {
      "x": 1
    }
  ]
}

AI uses your own key (several are free); a button opens a short setup.

About the JSON Formatter & Validator

Paste JSON to check it's valid and make it readable with indentation, or minify it into one line to make it smaller. If something is wrong, the error message says what and where.

How to use it

Paste your JSON into the input box.
Choose Pretty (2, 4 or 8 spaces) or Minify.
Copy or download the result.

Tip: An error like “Unexpected token” usually means a missing comma, an extra comma before } or ], or single quotes instead of double quotes.

Questions

Why is my JSON invalid?

JSON needs double quotes around keys and text, no comment lines and no comma after the last item. The error message points to the problem.

What is the difference between pretty and minified JSON?

Pretty JSON adds line breaks and indentation for people to read; minified JSON removes them so files are smaller and faster to send.

Is my data uploaded?

No. The tool runs in your browser; what you paste or open never leaves your device and nothing is stored on a server.