JSON Formatter
Format, minify & validate JSON data
What is JSON Formatter?
JSON Formatter is a tool that takes raw or minified JSON data and reformats it with proper indentation and line breaks for readability. It also validates your JSON syntax and pinpoints errors with line numbers, and can minify formatted JSON to reduce file size for production use.
How to Use
- Paste your JSON data into the input field.
- Click Format to pretty-print it with indentation, or Minify to compress it to a single line.
- If there are syntax errors, the tool will display the error location to help you fix it.
Frequently Asked Questions
What are common JSON syntax errors?
Trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and missing commas between properties are the most frequent mistakes. Another common issue is including JavaScript-specific values like undefined, NaN, or Infinity which aren't valid in JSON. This tool pinpoints the exact line number of syntax errors to help you fix them quickly.
What is the difference between JSON and a JavaScript object?
JSON requires double-quoted keys and string values, doesn't allow trailing commas, comments, or undefined. JavaScript objects are more permissive but can't be directly parsed as JSON. For example, {name: "Alice"} is valid JavaScript but invalid JSON-it must be {"name": "Alice"}. This distinction often trips up developers copying objects from code into configuration files.
Why minify JSON?
Minification removes whitespace and line breaks, reducing file size for network transfer. This is important for API responses and configuration files served to clients where bandwidth matters. A typical formatted JSON file can shrink 30-60% when minified. For production APIs serving millions of requests, this translates to significant bandwidth and cost savings.
