JSON Formatter & Validator - Format JSON Online Free
Free online JSON formatter and validator. Beautify, minify, and validate JSON data instantly in your browser. No data sent to any server.
What is JSON Formatter?
A JSON Formatter is a tool that takes raw or minified JSON (JavaScript Object Notation) data and reformats it with proper indentation and line breaks, making it easy to read and debug. JSON is the most widely used data format for APIs, configuration files, and data exchange between applications. When JSON is minified or poorly formatted, it becomes nearly impossible to read. This tool instantly formats your JSON with customizable indentation, validates its structure, and highlights any syntax errors. All processing happens entirely in your browser — your data never leaves your device.
How to Use
- Paste your JSON data into the input area on the left.
- Choose 'Format' to beautify with indentation, or 'Minify' to compress.
- Select your preferred indentation (2 or 4 spaces).
- The formatted result appears instantly on the right. Click 'Copy' to copy it.
Features
- Instant JSON formatting with customizable indentation
- One-click minification to compress JSON
- Real-time syntax validation with error messages
- 100% client-side processing — your data stays in your browser
- Works with any valid JSON including nested objects and arrays
- Copy formatted output with one click
Frequently Asked Questions
Is my data safe when using this JSON formatter?▾
Yes, absolutely. All processing happens entirely in your browser using JavaScript. Your JSON data is never uploaded to any server, making this tool completely safe for sensitive data.
What is valid JSON?▾
Valid JSON must use double quotes for strings, cannot have trailing commas, and must start with an object {} or array []. Keys must be strings. Values can be strings, numbers, booleans, null, objects, or arrays.
What is the difference between formatting and minifying?▾
Formatting adds indentation and line breaks to make JSON human-readable. Minifying removes all unnecessary whitespace to reduce file size, which is useful for production APIs and data transfer.
Can this tool handle large JSON files?▾
Yes, this tool handles JSON files of any reasonable size. Since it runs in your browser, performance depends on your device. Files up to several megabytes process instantly on modern devices.