Paste JSON
Paste your JSON data into the editor. The tool validates it instantly and highlights any errors with line numbers.
JSON Formatter & Validator
Format, beautify, validate, and minify your JSON data instantly. Syntax highlighting with line numbers and real-time error detection. 100% free, works in your browser.
Runs in your browser
JSON Formatting Tool
How It Works
Format or Minify
Click "Format" to prettify with indentation, or "Minify" to compress. Choose your preferred indent size.
Copy or Download
Copy the formatted JSON to your clipboard or download it as a .json file. View statistics about your data structure.
Features
Real-time Validation
Instantly validates your JSON as you type. Errors are highlighted with precise line and column numbers.
Syntax Highlighting
Professional code editor with syntax highlighting for keys, strings, numbers, booleans, and null values.
Format & Minify
Beautify JSON with customizable indentation (2 or 4 spaces), or minify to reduce file size.
Statistics
View detailed statistics about your JSON: count of objects, arrays, strings, numbers, nesting depth, and file size.
Line Numbers
Navigate large JSON files easily with line numbers. Error locations are shown with exact line and column references.
100% Private
All processing happens in your browser. Your JSON data is never sent to any server. Completely secure.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It is based on a subset of JavaScript syntax and is language-independent.
JSON is commonly used for:
- API responses - Most REST APIs return data in JSON format
- Configuration files - package.json, tsconfig.json, and many more
- Data storage - NoSQL databases like MongoDB store documents as JSON
- Data exchange - Transfer data between client and server applications
Common JSON Errors & How to Fix Them
- Missing comma: Make sure to add commas between key-value pairs and array elements. The last item should NOT have a trailing comma.
- Single quotes: JSON requires double quotes for strings. Use "key" not 'key'.
- Unquoted keys: All keys must be wrapped in double quotes. Use "name" not name.
- Comments: JSON does not support comments. Remove any // or /* */ style comments.
- Undefined/NaN: JSON only supports null, not undefined or NaN. Use null or omit the field.
Frequently Asked Questions
Yes, this JSON formatter is completely free with no limits on usage. All features including formatting, validation, conversion (YAML, XML, CSV, TypeScript), tree view, and diff comparison are available at no cost. No signup or account required.
Absolutely. All processing happens entirely in your browser using JavaScript. Your JSON data is never sent to any server or stored anywhere. This makes it completely safe to format sensitive configuration files, API responses, or any confidential data.
You can convert JSON to YAML (great for configuration files), XML (for legacy systems), CSV (for spreadsheet-compatible data from arrays), and TypeScript interfaces (for type definitions). Each conversion has customizable options to fit your needs.
Use the Diff tab to compare two JSON documents. Paste or type JSON in both panels, and the tool will highlight differences: additions appear in green, deletions in red, and changes in yellow. You can export the diff results as a text file for documentation.
Ctrl+Enter (Cmd+Enter on Mac) formats JSON, Ctrl+Shift+Enter minifies it, Ctrl+G (Cmd+G) opens the jump to line dialog, and F3/Shift+F3 navigates search results. These shortcuts help you work faster without reaching for the mouse.
The tree view presents your JSON as an interactive hierarchy with collapsible nodes. You can expand/collapse objects and arrays, search for values (matching nodes auto-expand), click any node to copy its path (e.g., 'data.users[0].name'), and see statistics about your data structure.
Common JSON errors include: missing commas between items, trailing commas (not allowed in JSON), using single quotes instead of double quotes, unquoted property names, and comments (not supported in JSON). The error message shows the exact line and column where the issue was detected.
Yes, your JSON is automatically saved to your browser's local storage as you type. When you return to the page, your last JSON content will be restored. You can also download your formatted JSON as a .json file at any time.