const data = {
name: "John Doe",
age: 30,
skills: ["JavaScript", "Python", "TypeScript"]
};
// Beautify with 2 spaces
const formatted = JSON.stringify(data, null, 2);
console.log(formatted);
// Minify
const minified = JSON.stringify(data);
console.log(minified);I built this JSON formatter after countless hours debugging API responses and config files with malformed JSON. Whether you're a backend developer testing REST APIs, a frontend engineer working with configuration files, or a DevOps specialist managing deployment manifests, clean JSON formatting is essential. This tool instantly validates your JSON syntax, highlights errors with line numbers, and beautifies minified data into readable, properly indented format. Unlike desktop editors that require installation, this runs entirely in your browser with zero data leaving your machine—perfect for handling sensitive production configs or customer data.
How to Use
Paste or type your JSON into the input panel. The tool automatically validates syntax in real-time, showing errors with precise line and column numbers. For beautifying: click Format to convert minified JSON into readable indented format (2 or 4 spaces). For minifying: use Compact to remove whitespace and reduce file size for production. The tool handles nested objects, arrays, Unicode characters, and escaped strings correctly. Works great with API responses from curl commands, clipboard data from browser DevTools, or exported database records.
Common Use Cases & Examples
**API Response Debugging**: Copy a minified API response from Network tab, paste here to see the structure clearly and identify missing fields. **Config File Validation**: Before deploying nginx or kubernetes configs in JSON format, validate syntax to catch typos like trailing commas or unquoted keys. **Data Transformation**: Clean up exported data from databases or spreadsheets before importing into another system. **Learning JSON**: Students can paste examples and see properly formatted output to understand nesting and structure.
Limitations & Important Notes
This tool validates against standard JSON specification (RFC 8259). It does NOT support: JSON5 extensions (trailing commas, comments, unquoted keys), JSONC (JSON with Comments used by VS Code), or non-standard formats. For very large files (>10MB), performance may degrade—consider using command-line tools like jq for batch processing. The formatter preserves string content exactly as-is, so pre-escaped Unicode or HTML entities remain escaped.