JSON Formatter & Validator - Format JSON Online Free
Free JSON formatter and validator tool formats, validates, minifies JSON data instantly. Real-time validation, tree view, data cleaning options. Perfect for API testing and debugging. Copy & paste results - no signup required!
Advanced Settings
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JSON Validation
Real-time validation with detailed error messages showing exact line and column positions for quick debugging.
Multiple Views
Format, minify, or view as tree structure. Perfect for different use cases from API responses to config files.
Data Cleaning
Remove null values, empty objects/arrays, sort keys alphabetically, and escape Unicode characters automatically.
Why Use a JSON Formatter and Validator?
JSON is Everywhere in Modern Development
JSON (JavaScript Object Notation) is the universal data interchange format for APIs, configuration files, and data storage. Every API response you receive, every config file you edit, and most database interactions involve JSON. But raw JSON from APIs or logs often comes minified or poorly formatted - making it impossible to read without proper formatting.
Our free JSON formatter instantly beautifies messy JSON data, adds proper indentation, and highlights syntax errors. Whether you're debugging API responses, reviewing configuration files, or cleaning data exports, proper formatting saves hours of frustration. Use our URL encoder when working with JSON in URLs.
Real-Time Validation Catches Errors Fast
JSON syntax errors break applications immediately - missing commas, extra brackets, unquoted keys. Manual error hunting wastes time. Our JSON validator instantly identifies problems, pinpointing exact line and column numbers where errors occur.
Common JSON Use Cases
API Development & Testing
Format API responses for debugging. Validate request bodies before sending. Clean up test data by removing null or empty fields.
Configuration Files
Edit package.json, tsconfig.json, settings files. Validate syntax before deploying. Sort keys for better git diffs.
Data Processing
Clean data exports from databases. Remove unnecessary fields. Convert between formatted and minified for production.
Learning & Documentation
Understand complex API responses with tree view. Create readable examples for documentation. Teach JSON structure to beginners.
Understanding JSON Format Options
Formatted View
Human-readable format with proper indentation and line breaks. Choose 2, 4, or 8 space indentation based on your team's coding standards. Perfect for editing, reviewing, and understanding JSON structure.
Minified View
Compact format with all whitespace removed. Reduces file size by 30-50% for faster API responses and smaller storage. Use for production deployments and network transmission.
Tree View
Hierarchical structure visualization with ASCII art. Shows nested relationships clearly. Ideal for exploring complex API responses and understanding data relationships quickly.
Frequently Asked Questions
What's the difference between JSON and JavaScript objects?
JSON is a text format based on JavaScript object syntax but with stricter rules. JSON requires double quotes for keys and strings (JavaScript allows single quotes or no quotes for keys). JSON doesn't support functions, undefined, or comments. All valid JSON is valid JavaScript, but not all JavaScript objects are valid JSON.
Why does my JSON fail validation?
Common mistakes: trailing commas after the last item, single quotes instead of double quotes, unquoted property names, comments (JSON doesn't support them), undefined values, or functions. Our validator shows exact error locations. Check for missing/extra brackets, commas, or quotes at the indicated line and column.
Should I minify JSON for production?
Yes, for API responses and data transmission. Minifying removes unnecessary whitespace, reducing bandwidth usage and speeding up transfers. However, keep formatted versions in source control for readability. Most build tools can automate this - minify for deployment, keep formatted for development.
How do I handle large JSON files?
Our tool processes JSON entirely in your browser, so file size depends on your device's memory. Files up to 10MB usually work fine. For larger files, use tree view (lighter on rendering) or command-line tools like jq. Consider breaking large JSON into smaller chunks or streaming if working with massive datasets.
What does "sort keys" do?
Alphabetically orders object properties. Useful for comparing JSON files (sorted keys produce cleaner diffs), creating consistent output, and finding properties quickly in large objects. Note: JavaScript objects maintain insertion order since ES2015, but sorting still helps human readability and version control.
Why remove null or empty values?
API responses often include null fields for optional data, bloating payload size. Removing nulls and empty objects/arrays reduces response size by 20-40% in some cases. Useful for cleaning data exports or preparing minimal API payloads. However, be careful - null has semantic meaning (explicitly absent) vs undefined (never set).
Can I convert JSON to other formats?
This tool focuses on JSON formatting and validation. For format conversion, you'll need specialized tools: JSON to CSV for spreadsheets, JSON to XML for legacy systems, JSON to YAML for configs. However, you can use our formatted output as readable source for manual conversion or copy to other converter tools.
Is my JSON data safe when using this tool?
Absolutely! All JSON processing happens entirely in your browser using JavaScript. Your data never leaves your computer - we don't send it to any server, don't store it, and don't track what you format. You can even use this tool offline after the page loads. Perfect for sensitive data like API keys or personal information.
Related Developer Tools
Enhance your development workflow with these complementary tools:
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Encode JSON data for URL parameters and query strings in APIs.
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Generate checksums for JSON files to verify data integrity.
Case Converter
Convert JSON property names between camelCase, snake_case formats.
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Count characters and file size of formatted vs minified JSON.
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