JSON Formatter — Format, Validate & Minify JSON Online

Use the full SmartDevTools JSON Editor above to format, validate, minify and explore JSON. It is the same workspace available on our main developer tools website, with tree view, JSONPath and JSON Tools.

What does a JSON formatter do?

A JSON formatter (also called a pretty-printer or beautifier) re-indents raw or minified JSON with consistent spacing and line breaks, making deeply nested objects and arrays easy to read and debug. It also validates the JSON as you type, flagging syntax errors like missing commas, unquoted keys or trailing commas with the exact error location.

Format, minify or sort — your choice

Switch between a fully indented "pretty" view for readability, a minified single-line view for production payloads, or a key-sorted view for consistent diffs — all from the same input.

JSON formatting example

Paste this compact JSON into the input pane, then click Format:

{"name":"Ada","active":true,"roles":["developer","reviewer"]}

The formatted result preserves the values while making the structure easier to read:

{
  "name": "Ada",
  "active": true,
  "roles": [
    "developer",
    "reviewer"
  ]
}

Use Validate to check syntax, Minify for a compact result, and Copy to copy the output. A trailing comma, such as in {"name":"Ada",}, is not valid JSON; remove it before formatting.

Frequently asked questions

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