JSON Formatter & Validator
Paste or type raw JSON below to validate, prettify, or minify it instantly. Parse errors are shown with position details so you can fix issues fast. Everything runs in your browser - your data never leaves your machine.
Try These Examples
User profile- A typical user object with nested address and roles arrayAPI response- A paginated API response with metadata and resultsConfig file- An application configuration object with feature flags
How It Works
This tool leverages two built-in JavaScript methods to handle all formatting and validation:
JSON.parse(input)- Takes a JSON string and converts it into a JavaScript value. If the string is not valid JSON, it throws aSyntaxErrorwith a message describing where the parse failed, including the position in the string.JSON.stringify(value, null, 2)- Converts a JavaScript value back into a JSON string. The third argument controls indentation: pass2for two-space pretty printing, or omit it entirely to produce minified output with no whitespace.
Because both methods are native to every modern browser's JavaScript engine, this tool requires no external libraries and works entirely offline once the page has loaded.
Frequently Asked Questions
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based data-interchange format. It is easy for humans to read and write and easy for machines to parse and generate. JSON is built on two structures: key-value pairs (objects) and ordered lists (arrays).
How does this JSON formatter work?
This tool uses JavaScript's built-in JSON.parse() to validate your input and JSON.stringify() with a spacing argument to pretty-print or minify it. Everything runs client-side in your browser - your data is never sent to a server.
What causes a JSON parse error?
Common causes include trailing commas after the last item in an object or array, single quotes instead of double quotes around keys and strings, unquoted keys, missing commas between items, and unescaped special characters inside strings.
Is my data safe when using this tool?
Yes. This tool is 100% client-side. Your JSON never leaves your browser - there are no network requests, no server processing, and no data storage. You can verify this by opening your browser's Network tab while using the tool.