JSON Formatter & Validator
Beautify, validate, and minify JSON data with syntax highlighting and detailed error messages.
Free Online JSON Formatter & Validator
This tool formats (beautifies), validates, and minifies JSON data directly in your browser. It provides syntax highlighting with distinct colors for keys, strings, numbers, booleans, and null values, making it easy to read and debug complex JSON structures. No data is sent to any server — everything runs locally in your browser.
Features
Format/Beautify adds proper indentation and line breaks to compressed JSON. Minify removes all whitespace to produce the smallest possible output. Validate checks JSON syntax and shows precise error locations. Sort Keys alphabetically orders all object keys at every nesting level. Choose between 2-space, 4-space, or tab indentation. Syntax highlighting colors keys, strings, numbers, booleans, and null distinctly.
Common JSON Errors
The most frequent JSON mistakes include trailing commas after the last item in an array or object, single quotes instead of double quotes around keys and strings, unquoted keys, comments (JSON doesn't support comments), and missing commas between items. This validator pinpoints the exact position of syntax errors to help you fix them quickly.
Frequently Asked Questions
JSON (JavaScript Object Notation) is a lightweight data format used for storing and exchanging data between a server and a web application. It's human-readable and is the most common format for REST APIs, configuration files, and data storage.
JSON is stricter than JavaScript: all keys must be double-quoted strings, it only supports basic data types (string, number, boolean, null, array, object), and it doesn't allow comments, trailing commas, or undefined values. JavaScript objects are more flexible but not directly interchangeable with JSON.
No hard limit — the tool handles large JSON files efficiently since everything runs in your browser. Files over 10MB may cause slight delays depending on your device.