# JSON Formatter & Validator — Free Online Tool
https://json.usetool.org/

> JSON Formatter is a free, privacy-first online tool for formatting, validating, and exploring JSON data. Features syntax highlighting, collapsible tree view, JSONPath queries, and detailed error messages. No signup, no ads, no server processing — everything runs in your browser.

## Features
- Format/beautify JSON with customizable indentation (2/4 spaces, tabs)
- Minify JSON (remove whitespace)
- Validate JSON with detailed error messages and line numbers
- Collapsible tree view for exploring nested structures
- JSONPath query support for filtering data
- Syntax highlighting with color-coded types (strings, numbers, booleans, null)
- One-click copy formatted/minified output
- Statistics: key count, depth, size
- Dark mode support
- Mobile responsive design
- Works offline after first load

## Use Cases
Developers debugging API responses, formatting config files, validating JSON schemas, exploring large nested objects, extracting data with JSONPath queries, minifying JSON for production, comparing JSON structures.

## Limitations
No JSON Schema validation. No JSON diff/comparison. No JSON-to-YAML/XML conversion (use separate converters). No streaming parser for very large files (>50MB may be slow). No API — all processing is client-side in the browser.

## Technical
Built with Astro 5 (static site generator), Preact + Signals, Tailwind CSS. Uses native JSON.parse() for validation and custom tree renderer. Text never leaves the browser. Part of the UseTool suite at usetool.org.