JSON Formatter & Validator
Format, validate, and beautify JSON with syntax highlighting. Press Ctrl+Enter to format or Ctrl+K to clear.
Output will appear here...About JSON Formatter
Ever copied an API response and found yourself staring at a wall of text? That's the reality of minified JSON. Our formatter takes that mess and turns it into something readable. Paste your data, hit format, and suddenly you can actually see the structure.
But this isn't just about making things pretty. The validator catches syntax errors before they cause problems in production. Missing comma on line 47? We'll tell you exactly where. Unclosed bracket somewhere in a 500-line file? The error message shows the precise location with line and column numbers.
Features
- Format JSON: Pretty-print minified JSON with configurable indentation (2 spaces, 4 spaces, or tabs)
- Minify JSON: Remove all whitespace to create compact JSON strings
- Validate JSON: Real-time syntax validation with precise error messages showing line and column numbers
- Schema Validation: Validate JSON data against JSON Schema (Draft 7) with detailed error reporting
- File Upload: Drag and drop JSON files or use the file picker
- Keyboard Shortcuts: Ctrl+Enter to format, Ctrl+K to clear
- Privacy First: All processing happens in your browser - your data never leaves your machine
Common Use Cases
- Debug API responses that come back minified from production servers
- Validate configuration files before deploying to staging or production
- Check JSON schema compliance for API contracts and data structures
- Track down syntax errors in large JSON files without manual inspection
- Reduce file size by minifying JSON for network transfer
- Standardize indentation across team codebases for better readability
The schema validation tab deserves special mention. Drop in your JSON Schema (Draft 7), paste your data, and find out if they match. It's particularly useful when you're building or consuming an API and need to ensure data structures align with the contract. The validator catches type mismatches, missing required fields, and constraint violations—all the things that would otherwise blow up at runtime.
Frequently Asked Questions
Is my JSON data safe?
Yes. Everything happens in your browser. We don't have servers collecting your data because there's nothing to collect—the code runs entirely on your machine. You could disconnect from the internet after loading the page and it would still work. That's intentional. Your customer data, internal configs, and proprietary API responses stay on your device.
What's the maximum JSON file size I can format?
We can handle files up to 10MB without breaking a sweat. Larger files take a few seconds to process, but modern browsers can manage the load. If you're formatting massive datasets regularly, though, you might want to consider doing it programmatically with a JSON library in your codebase.
How do I fix "Unexpected token" errors?
These usually point to syntax problems—missing commas between properties, extra commas before closing brackets, unclosed strings, or bracket mismatches. Check the line number in the error message. Look at that line and the one before it. Nine times out of ten, the issue is there. Common culprits: trailing commas after the last property (JSON doesn't allow those), single quotes instead of double quotes, or forgetting to close a nested object.
What is JSON Schema validation?
Think of it as a contract for your JSON. The schema defines what properties are required, what types they should be, and what constraints they must satisfy. When you validate data against a schema, you're checking if the data meets all those requirements. It's incredibly useful for API development—both when building APIs (to validate incoming requests) and when consuming them (to verify responses match the documentation).
Which JSON Schema version is supported?
This tool supports JSON Schema Draft 7, which includes type validation, required properties, string patterns, numeric constraints (minimum/maximum), array validation, and format validation for common types like email, date-time, URI, and more.