JSON Debugger
Real-time formatting with intelligent error detection
Input
Output
JSON Formatter & Validator — Free Online Tool
inspectly.dev's JSON Formatter instantly formats, validates, and debugs JSON data in your browser. Paste any JSON string and get syntax highlighting, error detection with exact line numbers, nested tree view, path finder, and side-by-side diff comparison — all without sending your data to any server.
Key Features
- Instant JSON formatting with configurable indentation (2 or 4 spaces)
- Real-time syntax validation with error highlighting and line numbers
- Collapsible tree view for exploring deeply nested structures
- JSON Path Finder — click any value to copy its full access path
- Side-by-side JSON Diff to spot differences between two objects
- Minify JSON to reduce payload size
- Copy formatted output to clipboard with one click
- 100% client-side — no data sent to any server
Common Use Cases
- Debugging API responses from REST or GraphQL endpoints
- Validating JSON configuration files before deployment
- Understanding unfamiliar JSON structures from third-party APIs
- Comparing JSON payloads to find differences between versions
- Finding the correct path to nested fields in complex JSON
- Preparing JSON data for documentation or bug reports
Frequently Asked Questions
How do I format JSON online for free?
Paste your JSON into the editor at inspectly.dev/json and it formats automatically. No sign-up or account required. The tool detects syntax errors and shows exactly which line is broken.
Why is my JSON showing a validation error?
Common JSON errors include trailing commas (not allowed in JSON), single quotes instead of double quotes, unquoted property names, and missing commas between items. The validator highlights the exact line where the error occurs.
Is my JSON data safe to paste here?
Yes. All processing happens entirely in your browser using JavaScript. Your JSON data is never uploaded to any server, logged, or stored. You can verify this by checking the browser's network tab — no requests are made.
What is the difference between JSON formatting and minification?
Formatting (pretty-printing) adds indentation and line breaks to make JSON readable for humans. Minification removes all whitespace to reduce file size — useful for API payloads and storage. This tool supports both.