JSON Formatter
Format, validate, and minify JSON data instantly. Syntax highlighting, error detection with line numbers, and download as .json file. Perfect for developers working with APIs and data.
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How to Use
Paste your JSON
Copy and paste your JSON data into the input area. The tool accepts any valid JSON format, including objects, arrays, and nested structures.
Choose an action
Click "Format" to prettify your JSON with proper indentation (choose 2 or 4 spaces), "Minify" to compress it by removing whitespace, or "Validate" to check for syntax errors.
View the result
The formatted or minified JSON appears in the output panel with syntax highlighting. Colors help you identify strings (green), numbers (blue), booleans (purple), and keys (orange).
Check for errors
If your JSON has syntax errors, the Validate action shows exactly where the problem is with line and column numbers, plus a helpful error message and code snippet.
Copy or download
Click "Copy" to copy the result to your clipboard, or "Download" to save it as a .json file. The tool also shows statistics like character count and size reduction for minified JSON.
Frequently Asked Questions
What's the difference between Format and Minify?
Format (or prettify) adds proper indentation, line breaks, and spacing to make JSON human-readable. It's perfect for debugging or reviewing API responses. Minify does the opposite—it removes all unnecessary whitespace to create the smallest possible file size. Use minify when you need to reduce bandwidth or storage, like when sending JSON over a network. The tool shows you exactly how many bytes you save when minifying.
Why is my JSON invalid?
Common JSON syntax errors include: missing commas between properties, trailing commas after the last item (not allowed in JSON), unquoted keys (keys must be in double quotes), single quotes instead of double quotes (JSON requires double quotes), and comments (JSON doesn't support comments). The Validate action shows you exactly where the error is with line and column numbers, plus a code snippet highlighting the problem. Fix the error and validate again.
Can I format very large JSON files?
Yes! The tool handles JSON files up to 100KB efficiently. For very large files, the tool automatically optimizes performance by debouncing input and may disable syntax highlighting to keep things fast. All processing happens in your browser—your JSON is never uploaded to any server. If you're working with massive JSON files (>1MB), consider using a desktop tool or command-line utility for better performance.
What do the different colors mean in the output?
The syntax highlighting uses colors to help you read JSON more easily: Green for string values, Blue for numbers, Purple for booleans (true/false), Gray for null values, Orange for object keys (property names), and Dark gray for punctuation (braces, brackets, colons, commas). This color coding makes it much easier to spot data types and structure at a glance, especially in complex nested JSON.