JSON Formatter & Validator

About the JSON Formatter & Validator

Paste raw or minified JSON and the formatter pretty-prints it with 2-space, 4-space or tab indentation, or minifies it back to one line. Parsing happens in your browser, so a syntax error is reported as soon as the text stops being valid JSON.

It is a formatter and a syntax checker, not a schema validator: it tells you whether the text parses, not whether the values match the shape your API expects.

How to use it

1. Paste or type your JSON into the Raw Input box, or press Sample JSON to load an example.
2. Pick 2 Spaces, 4 Spaces or Tab for pretty-printing, or Minify for a single line.
3. Read any error, notice or warning shown above the output, then press Copy Output.

Worked example

Formatted with the 2 Spaces option.

{"name":"Ada","langs":["JS","Go"],"active":true}

{
  "name": "Ada",
  "langs": [
    "JS",
    "Go"
  ],
  "active": true
}

Common mistakes and gotchas

• Trailing commas, single-quoted strings, unquoted keys and comments are not valid JSON. The tool may still read them as JSON5 and then shows a notice that the output was normalised, so check that the original is not what your parser receives.
• A repeated key keeps only its last value when parsed. The tool warns about duplicates so you notice before the earlier value disappears.
• Integers above 9007199254740991 (2^53 - 1) cannot be held exactly by JavaScript numbers. The tool lists such values so you can keep them as strings instead.
• NaN, Infinity and undefined have no JSON form and are reported as errors rather than silently becoming null.

Frequently asked questions