Format and validate JSON

Formatting is parsing: this tool runs your input through a real JSON parser and re-emits it with the indentation you pick. That makes it a validator too. If the input is not valid JSON you get the parser's error message instead of silently mangled output.

Indent

Input

Example

Input

{"name":"Ada","tags":["dev","math"],"active":true}

Output

{
  "name": "Ada",
  "tags": [
    "dev",
    "math"
  ],
  "active": true
}

One line in, structured output out. Arrays and nested objects each get their own indentation level.

Input and output

Input is any JSON value: an object, array, string, number, boolean, or null. Output is the same value re-serialized with your chosen indentation (2 spaces by default, 4 spaces or tabs via the Indent option).

Because the input is parsed and re-emitted, key order is preserved but formatting quirks are not: trailing whitespace, odd line breaks, and duplicate whitespace all normalize away. Invalid JSON (trailing commas, single quotes, unquoted keys) fails with the parse error so you can find the problem.

Privacy

This tool runs entirely in your browser. The input is never uploaded, logged, or stored; close the tab and it is gone. The one deliberate exception in the whole Toolbox is the explicit Save as new paste button on the output, which does exactly what it says and nothing before you press it.

Your JSON never leaves the page. That matters here because JSON blobs are exactly where API responses, config, and customer data live.

Common uses

Reading a minified API response while debugging
Cleaning up JSON before committing a fixture or config file
Checking whether a hand-edited JSON file is still valid
Formatting a JSON log line so a code review can actually read it

Need to share the result?

Run the tool, then use Save as new paste on the output to get a link you can send. The paste is unlisted, expires in a week, and the recipient needs no account. Or start from a blank paste if you already have the text.

Related tools

More tool pages: Decode Base64 to text, Decode a JWT, Generate UUIDs, Convert a Unix timestamp to a date, Convert CSV to JSON. Everything else lives in the full Toolbox, which also chains tools into workflows.