JSON Formatter & Validator
Validate, pretty-print, and minify JSON data instantly. Choose your indentation style, inspect structure stats, and catch syntax errors with clear messages. Free, private, and runs entirely in your browser.
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 is the most widely used format for APIs, configuration files, and data storage on the web. JSON supports six data types: strings, numbers, booleans, null, arrays, and objects. Despite its simplicity, JSON syntax errors are extremely common, particularly missing commas, unmatched brackets, and trailing commas (which are not allowed in strict JSON).
Why Format JSON?
Minified JSON is compact and efficient for transmission, but nearly impossible to read. Formatting (or "pretty-printing") adds indentation and line breaks so you can quickly understand the structure, spot nested objects, and identify values. This is essential when debugging API responses, reviewing configuration files, or inspecting data exports. Our formatter lets you choose between 2-space, 4-space, 8-space, or tab indentation to match your coding style.
When to Minify JSON
Minification removes all unnecessary whitespace from JSON, reducing file size for faster network transfer and smaller storage footprint. This is particularly useful when embedding JSON in HTML, sending payloads to APIs, or storing data in databases where every byte counts. Our minifier also validates the JSON before compressing it, so you can be confident the output is both valid and optimised.
Structure Analysis
The stats panel shows a breakdown of your JSON structure: total keys, maximum nesting depth, and counts of each data type (objects, arrays, strings, numbers, booleans, and nulls). This helps you understand the complexity of your data at a glance, which is useful when working with unfamiliar API responses or debugging deeply nested configurations.