JSON Formatter
Format, validate, and beautify JSON data
How to use
Paste JSON into the input area. The tool validates the syntax and formats it with proper indentation. Switch between formatted (pretty-printed) and minified output. Invalid JSON shows a clear error message with the location of the problem.
Examples
Debugging API responses
Paste a minified API response to see it with proper indentation and structure. This makes it much easier to find specific keys and understand nested data.
Validating configuration files
Paste a JSON config file to check for syntax errors like missing commas, unmatched brackets, or trailing commas before deploying.
Minifying for production
Switch to minify mode to remove all whitespace from JSON data, reducing payload size for network transfer or storage.
Frequently asked questions
What counts as valid JSON?
Valid JSON must use double quotes for keys and strings, cannot have trailing commas, and supports strings, numbers, booleans, null, arrays, and objects. Comments are not allowed in standard JSON.
Why is my JSON invalid?
Common issues include single quotes instead of double quotes, trailing commas after the last element, unescaped special characters in strings, and missing closing brackets or braces.
What indentation options are available?
The formatter uses 2-space indentation by default, which is the most common convention for JSON. The output is a valid, well-structured JSON string.
Can this tool handle large JSON files?
The tool works in your browser, so it can handle JSON up to several megabytes. Very large files (10MB+) may cause the browser to slow down.
Is my data safe?
Yes. All formatting and validation happens locally in your browser using the native JSON parser. No data is sent to any server.
About this tool
Format, validate, and beautify JSON data. Minify JSON, fix common errors, and view structured output. Free online JSON formatter.
All calculations are performed locally in your browser. Your data never leaves your device.