JSON Formatter & Validator

How to Format JSON Online for Free

Filator's free JSON formatter lets you beautify, validate, minify, and fix JSON instantly in your browser—no file uploads, no server processing, no signup required. Unlike JSONFormatter.org (has ads and tracking) and JSONLint.com (limited features), Filator processes everything locally on your device for complete privacy with advanced features like tree view, auto-fix errors, and syntax highlighting.

Why Choose Filator's JSON Formatter?

How to Format JSON Step-by-Step

1. 1.Paste your JSON into the input area or upload a JSON file (up to 10MB)
2. 2.Choose your formatting options: indentation size (2 or 4 spaces), syntax highlighting theme, and enable auto-fix if needed
3. 3.Click "Format" to beautify your JSON with proper indentation and line breaks, or "Minify" to compress it for production
4. 4.Use tree view to navigate complex structures, or click JSON Path to get paths for programmatic access
5. 5.Download formatted JSON, copy to clipboard, or share via URL—no email delivery or server processing delays

Filator vs Competitors Comparison

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that's easy for humans to read and write, and easy for machines to parse and generate. Originally derived from JavaScript, JSON has become the de facto standard for data exchange between web services, APIs, and configuration files across all programming languages.

Common JSON Errors and Auto-Fix Solutions

Our formatter automatically detects and can fix these common JSON errors:

• • Trailing Commas: Removes unnecessary commas before closing brackets (e.g., [1, 2, 3,] → [1, 2, 3])
• • Single Quotes: Converts single quotes to double quotes required by JSON spec ({'key': 'value'} → {"key": "value"})
• • Unquoted Keys: Adds quotes around object keys ({key: value} → {"key": "value"})
• • Python/JS Syntax: Converts language-specific values (True/False/None → true/false/null)
• • Missing Commas: Automatically adds commas between object properties where missing

Advanced Features

• • Syntax Highlighting: Multiple color themes with customizable syntax highlighting for better readability
• • Tree View Navigation: Interactive tree structure for exploring complex nested JSON objects and arrays
• • JSON Path Explorer: Click any value to get its JSONPath for programmatic access in your code
• • Table View: Display JSON arrays as sortable, filterable tables for easier data analysis
• • Schema Validation: Validate JSON against JSON Schema specifications to ensure data structure compliance
• • Sort Keys: Alphabetically sort object keys for consistent formatting and easier comparison
• • Remove Nulls: Strip null values and empty strings to reduce file size
• • Performance Metrics: See parse time, validation time, and file size statistics
• • Diff Viewer: Compare two JSON objects side-by-side to spot differences
• • Offline Support: Install as PWA to format JSON without internet after initial load

JSON in Different Programming Languages

JSON is supported natively in most modern programming languages:

• • JavaScript: JSON.parse() to decode, JSON.stringify() to encode
• • Python: json.loads() to decode, json.dumps() to encode
• • Java: Use libraries like Jackson (ObjectMapper) or Gson (Gson)
• • PHP: json_decode() to decode, json_encode() to encode
• • Go: json.Marshal() to encode, json.Unmarshal() to decode
• • Ruby: JSON.parse() to decode, JSON.generate() to encode
• • C#: JsonSerializer.Deserialize() and JsonSerializer.Serialize()

JSON Best Practices

1. 1.Consistent Naming: Use camelCase or snake_case consistently throughout your JSON structure
2. 2.Meaningful Keys: Use descriptive property names that clearly indicate the data they contain
3. 3.Avoid Deep Nesting: Keep structures reasonably flat (max 3-4 levels) for better performance and readability
4. 4.Use Arrays for Lists: Don't use numbered keys like {"item1": ..., "item2": ...}—use arrays instead
5. 5.ISO 8601 for Dates: Use standard date format 2025-01-27T10:30:00Z for interoperability
6. 6.Minify for Production: Remove whitespace in production APIs to reduce bandwidth
7. 7.Validate Before Deploy: Always validate JSON syntax before deploying config files or APIs

Common Use Cases

Frequently Asked Questions