JSON Toolkit — Format & Convert

A JSON formatter helps developers beautify and validate JSON data for better readability and debugging. It transforms minified JSON into a structured, human-readable format with proper indentation.

Yes. All tools are completely free and run locally in your browser. No signup, no limits, no hidden costs.

No. Your JSON data never leaves your browser. All processing happens locally on your device, ensuring complete privacy and security.

Simply paste your JSON into the input area and click the "Format" button. The tool will automatically add proper indentation and line breaks. You can also switch to "Tree View" for a navigable hierarchy.

Minification removes all unnecessary whitespace and line breaks from JSON, creating a compact single-line format ideal for production environments and network transmission.

Click the "Convert" tab and select "XML" as the target format. Paste your JSON and the tool generates well-formed XML with proper nesting. For example:

{\n  "book": {\n    "title": "JSON Guide",\n    "price": 29.99\n  }\n}

Converts to:

<book>\n  <title>JSON Guide</title>\n  <price>29.99</price>\n</book>

Yes! Click the "Validate" tab to check your JSON for syntax errors. The validator shows exact line numbers, character positions, and detailed error descriptions to help you fix issues quickly.

The validator will highlight the exact line and position of any syntax errors. Common errors include missing quotes around keys, trailing commas, or unescaped special characters.

Common issues include: unquoted keys (JavaScript objects are not JSON), single quotes instead of double quotes, trailing commas in arrays/objects, and unescaped newlines or tabs in strings.

Yes! Once you've visited the page, all functionality works offline thanks to service workers and local processing.

The practical limit depends on your browser's available memory. JSON files up to 10-20MB typically work well since the tool uses the browser's native JSON parser which is highly optimized. Extremely large files may cause tab crashes due to memory constraints. The tree view and JSONPath query features work best with files under 5MB.

JSON.stringify automatically omits properties with undefined values, converts functions to undefined (omitting them entirely from the output), and throws a TypeError for Symbol values used as property keys. This tool uses JSON.stringify internally for formatting. For custom serialization behavior, you can pass a replacer function or array as the second argument.

JSONPath is an XPath-like query language using expressions like $.store.book[0].title to navigate nested JSON structures with filters and wildcards. JMESPath is a more modern query language supporting projections, functions, pipes, and multi-select hashes. JSONPath is simpler for basic navigation, while JMESPath offers more powerful data transformation capabilities.

Converting JSON to language-specific type definitions saves significant development time when consuming JSON APIs. Each language has different type syntax — TypeScript uses interfaces, Java uses POJOs with Jackson annotations, Python uses dataclasses or TypedDict, Go uses structs with JSON tags, and C# uses classes with JsonProperty attributes. The tool handles all language-specific nuances automatically.

Serialization (JSON.stringify) converts a JavaScript object into a JSON string for transmission or storage. Deserialization (JSON.parse) converts a JSON string back into a JavaScript object. This tool's Format and Minify buttons use stringify internally, while Validate uses parse to check the input is well-formed JSON before processing.