JSON Central

Private by design

JSON Formatter Online

Format, validate, sort and minify JSON without sending a single character to a server. Everything runs locally in your browser—even large documents.

Open the formatter

Browser-local workbench

Format and validate

Nothing you enter leaves this device.

0 characters · 0 bytes

Waiting for JSON

Technical guide

What formatting changes

Formatting parses valid JSON and serialises it with consistent whitespace. Minifying removes that optional whitespace. Neither action changes strings, numbers, booleans, null values or array order. Optional key sorting creates a new output ordering; the source input remains untouched.

Working with large files

Processing happens in a separate browser thread so controls remain usable. Your device still needs enough memory to hold the original text, parsed data and output.

Common errors

Why JSON will not parse

  • Property names and strings require double quotes.
  • Trailing commas are not allowed.
  • Comments are not part of JSON.
  • Backslashes inside strings must form valid escapes.
  • undefined, NaN and Infinity are not JSON values.

The workbench reports the browser’s syntax error and a line and column when the runtime exposes enough position information.

Coming later

Related tools

JSON to CSV

Unavailable · future tool

JSON Diff

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JSON Schema

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FAQs

Questions, answered

Is my JSON uploaded?

No. Formatting, validation, files, copying and downloads stay inside your browser.

Does sorting change my input?

No. The editable input is never silently repaired or replaced. Sorting only affects generated output.

Can JSON begin with an array or primitive?

Yes. Valid root values include objects, arrays, strings, numbers, booleans and null.

Is JSON Central free?

This formatter is available without an account or payment.