Free online tool

JSON Formatter & Validator

Read JSON without rounding large IDs

Upload a file

Drop your file hereTap to choose a file

or click to browse, or paste from the clipboard

Keep original values

The formatter edits whitespace between tokens. It keeps large number literals, string escapes, member order and repeated names exactly as entered.

Pinpoint invalid syntax

A validation error includes a line and column so you can find a missing value, trailing comma or invalid token.

Explore nested data

Open the tree view for a document of up to 1,200 tokens and expand objects or arrays individually.

How to use the JSON Formatter & Validator

  1. 1

    Paste a JSON object, array or value into the input pane.

  2. 2

    Choose two or four spaces and select Format. Use Validate for a syntax check or Minify to remove whitespace outside strings.

  3. 3

    Explore the tree of a small document, copy the result or download document.json.

What people use this tool for

  • Inspect a webhook event without rounding numeric IDs.
  • Validate a configuration before saving it.
  • Produce compact JSON for a fixture.

Frequently Asked Questions

Does formatting change large integer IDs?

Numbers keep their original spelling, including integers larger than the JavaScript safe integer range, exponents and negative zero.

What can I validate?

The validator accepts JSON syntax including top-level strings, numbers and arrays. It rejects comments and trailing commas. It does not check a JSON Schema.

What are the size limits?

Use up to 524,288 input characters and 128 levels of nesting. Formatted output is limited to 4,194,304 characters.