jsonfmt

JSON formatter and validator

Paste JSON to format, validate, minify or convert it to CSV and XML. It runs in your browser, so nothing you paste is uploaded.

Indent
Input
Formatted JSON

Output will appear here

Open full screen

How it works

From messy payload to readable JSON in seconds

  1. Paste your JSON

    Valid JSON is pretty-printed as you paste. Invalid JSON shows the line and column of the first error.

  2. Pick an output

    Beautify with 2 or 4 spaces and sorted keys, minify it, browse it as a collapsible tree, or convert it to CSV or XML.

  3. Copy or download

    One click copies the result. Download saves it as .json, .csv or .xml.

Features

A JSON tool that stays out of your way

  • Private by design

    Everything runs in your browser. Your JSON never leaves your device, so it is safe for API keys and customer data.

  • Errors you can act on

    Line and column for the first syntax error, with the parser message, instead of a red "invalid" badge.

  • Five views of the same data

    Formatted, minified, collapsible tree, CSV and XML, switchable without re-pasting.

  • Readable highlighting

    Keys, strings, numbers, booleans and null each get their own colour, tuned for both dark and light mode.

  • No ads, no sign-up

    Open the page and paste. Nothing to install and nothing to log in to.

  • Sample data on tap

    Need something to test with? Generate a random JSON document in one click.

Guides

Learn the format, fix the errors

FAQ

Questions developers ask

No. Formatting, validation and conversion all run in your browser with JavaScript. Nothing you paste is uploaded or stored.

Paste it in. The input pane marks it Invalid JSON and shows the line and column where parsing failed, with the parser message. Common causes are trailing commas, single quotes and unquoted keys.

Beautify adds indentation and line breaks (2 or 4 spaces, with optional key sorting) so JSON is easy to read. Minify removes all optional whitespace so the payload is as small as possible.

Yes. Switch the output to CSV for an array of objects (one row per object, one column per key) or to XML, where you can set the root tag. Copy the result or download it as a file.

No. It is free, has no ads and needs no sign-up.