Lightning Fast
Instant validation and formatting
100% Private
Your data never leaves your browser
Large Files
Handle files up to 10MB with ease
Developer First
Built with Monaco Editor (VS Code)
Why lookatjson.com?
Lightning Performance
Instant JSON formatting with zero lag. Handle massive files up to 10MB without breaking a sweat. Our Monaco Editor engine ensures smooth scrolling and editing even with complex nested structures.
Complete Privacy
Your JSON never leaves your browser. All processing happens locally using client-side JavaScript. No servers, no tracking, no data collection. Perfect for sensitive API keys and confidential data.
Developer First
Built with VS Code's Monaco Editor. Get syntax highlighting, intelligent folding, multi-cursor editing, and all the powerful features you love. It's like having VS Code in your browser.
How to Format JSON Online
Get started in seconds with our simple workflow
Input Your JSON
Paste directly into the editor, drag and drop a .json file, or click Import to browse. The editor accepts any valid JSON structure and provides instant feedback.
Automatic Validation
Watch as your JSON is validated in real-time. Green means valid, red shows exactly where errors are with line and column numbers. No more hunting for that missing comma!
Export Your Data
Copy formatted JSON to clipboard with one click or download as a file. Use the Format button to beautify, or Collapse/Expand to navigate large structures easily.
Understanding JSON Format
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based data format that's easy for humans to read and machines to parse. It's the standard for modern APIs and web services.
JSON Structure Example
{
"user": {
"name": "John Doe",
"age": 30,
"email": "john@example.com"
},
"preferences": {
"theme": "dark",
"notifications": true
},
"tags": ["developer", "json", "api"]
}Frequently Asked Questions
What's the maximum file size?
Our JSON viewer efficiently handles files up to 10MB. For larger files, we use progressive rendering and virtual scrolling to maintain performance. The actual limit depends on your browser's available memory.
Is my data secure?
Absolutely! All JSON processing happens in your browser. No data is sent to servers, stored, or logged. This makes lookatjson.com perfect for handling sensitive data like API keys, passwords, or confidential information.
Can I edit JSON directly?
Yes! The Monaco Editor allows full editing capabilities. You get syntax highlighting, auto-completion, error detection, and multi-cursor editing - all the features from VS Code right in your browser.
Does it work offline?
After your first visit, lookatjson.com works offline thanks to service worker caching. You can format and validate JSON without an internet connection - perfect for development environments with limited connectivity.
JSON Best Practices
- •Always use double quotes for strings
- •No trailing commas after last item
- •Use consistent indentation (2 or 4 spaces)
- •Keep property names descriptive
- •Validate before production use
Common Use Cases
- •REST APIs: Request/response payloads
- •Config Files: package.json, settings
- •NoSQL: Document storage format
- •Mobile Apps: Server communication
- •Data Export: Portable data format