Paste your JSON to format, prettify, minify, or validate it instantly. Errors are highlighted with position information so you can fix issues quickly. All processing happens in your browser — nothing is sent to a server.
JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. APIs, configuration files, and databases all rely on properly structured JSON. Whether you are debugging an API response, cleaning up a config file, or preparing data for import, this tool helps you work with JSON efficiently.
About This Tool
The JSON Formatter and Validator provides three core functions:
Format / Prettify — adds indentation and line breaks so the JSON is easy to read and review
Minify — removes all unnecessary whitespace to produce the smallest possible output
Validate — checks that the JSON is syntactically correct and reports the exact error position if not
All processing runs entirely in your browser using the built-in JSON.parse() and JSON.stringify() functions. No data is transmitted or stored. You can choose between 2-space, 4-space, or tab indentation depending on your project's coding style.
FAQ
What are the basic JSON syntax rules?
JSON data is built from two structures: objects (key-value pairs wrapped in curly braces) and arrays (ordered lists wrapped in square brackets). Keys must be double-quoted strings. Values can be strings (double-quoted), numbers, booleans (true/false), null, objects, or arrays. Trailing commas are not allowed, and single quotes cannot be used in place of double quotes.
How does JSON validation work?
This tool uses the browser's built-in JSON.parse() function to validate your input. If the JSON is malformed, the parser throws an error that includes the position (character offset) where it encountered the problem. The tool displays this information so you can locate and fix the issue in your original text.
What are the most common JSON errors?
The most frequent mistakes are: missing or extra commas between elements, using single quotes instead of double quotes around keys or string values, trailing commas after the last item in an object or array, unescaped special characters inside strings (like literal newlines or tabs), and forgetting to wrap keys in quotes. This tool highlights the exact position of the first error found.
What is the difference between JSON.stringify and JSON.parse?
JSON.parse() takes a JSON string and converts it into a JavaScript object or value. JSON.stringify() does the opposite — it takes a JavaScript value and converts it into a JSON string. When you format JSON, this tool first parses the input to verify it is valid, then stringifies it back with the chosen indentation to produce the prettified output.