Free Online JSON Formatter & Validator

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It has become the de facto standard for data exchange in web APIs, configuration files, and data storage.

JSON is built on two structures: a collection of key-value pairs (objects) and an ordered list of values (arrays). These universal data structures are supported by virtually every modern programming language, making JSON an ideal format for cross-platform communication.

How to Format JSON Online

Using our JSON formatter is straightforward:

1. Paste your JSON into the input panel on the left
2. Click "Format 2-sp" or "Format 4-sp" to beautify your JSON with the desired indentation
3. Copy or download the formatted result from the output panel

The formatter automatically validates your JSON as you type, showing error messages with position information to help you quickly find and fix syntax issues.

JSON Formatting vs Minification

Formatting (or "beautifying") adds indentation and line breaks to make JSON human-readable. This is useful during development and debugging. Minification removes all unnecessary whitespace, reducing file size for production use and API responses. Our tool supports both operations with a single click.

Common JSON Errors

The most frequent JSON syntax errors include: trailing commas after the last element in an array or object, single quotes instead of double quotes around keys and strings, unquoted keys, and missing commas between elements. Our validator detects all of these and reports the approximate error position.