Free JSON Formatter
Free online tool to format, validate, auto-fix and prettify JSON data in your browser. Complete client-side security.
What is JSON and Why Use a Formatter?
JSON (JavaScript Object Notation) is a lightweight, human-readable data-interchange format. It is the de facto standard for APIs, web application state, and configuration files. However, raw JSON generated by servers is often minified (devoid of spacing or line breaks), making it extremely hard for developers to read or debug.
A JSON Formatter takes messy or minified JSON strings and converts them into a beautiful, hierarchical tree format with proper indentation, color-coding, and syntax validation.
How This JSON Validator Works
This formatter runs entirely inside your browser. Your data is never transmitted to any external server. It parses the input using advanced client-side JavaScript, validates it against standard JSON rules, and automatically flags syntax errors (like missing commas, trailing commas, or unquoted keys) with precise line numbers so you can fix them immediately.