JSON Formatter/Validator
Format, validate, and beautify JSON
JSON Formatter & Validator
How to Use
- Paste or type your JSON in the input field
- The validator will automatically check for syntax errors
- Click Format to pretty-print with indentation
- Click Minify to remove all whitespace
- Use the indent dropdown to adjust spacing
Your Privacy is Protected
All processing happens entirely in your browser. No data is stored, transmitted, or tracked. Your information remains completely private and secure on your device.
About JSON Formatter and Validator
Format, validate, and beautify JSON data instantly with our comprehensive JSON formatter and validator tool. JSON (JavaScript Object Notation) is the universal data interchange format used in APIs, configuration files, databases, and web applications. Our tool helps developers work with JSON by providing syntax validation, automatic formatting with proper indentation, error detection with precise line numbers, minification for production, and instant beautification of messy JSON. Essential for API development, debugging responses, creating configuration files, testing data structures, and learning JSON syntax. The validator catches syntax errors like missing commas, unclosed brackets, invalid quotes, and malformed structure. The formatter transforms ugly one-line JSON into readable, properly indented format. Perfect for developers, QA testers, data analysts, and anyone working with JSON data regularly.
Key Features
Syntax Validation
Instantly validates JSON syntax and structure. Identifies errors with exact line and column numbers, explaining what's wrong and how to fix it.
Beautiful Formatting
Transform minified or messy JSON into properly indented, readable format. Customizable indentation (2 or 4 spaces, or tabs) for personal preference or team standards.
JSON Minification
Remove all whitespace, newlines, and unnecessary characters to create compact JSON. Reduces file size for production, storage, or transmission.
Error Detection and Highlighting
Pinpoints syntax errors with detailed messages. Shows exact error location, suggests fixes, and explains common JSON mistakes.
Tree View Visualization
View JSON structure as an interactive tree. Collapse and expand objects and arrays to navigate complex JSON structures easily.
Schema Validation
Validate JSON against JSON Schema to ensure data structure meets requirements. Perfect for API contract validation and data quality checks.
Escape/Unescape Strings
Properly escape or unescape special characters in JSON strings. Handle quotes, backslashes, newlines, and unicode characters correctly.
JSON to Different Formats
Preview JSON data in different formats: compact, expanded, as JavaScript object, or as string literal. Copy in your preferred format.
How to Use JSON Formatter/Validator
Paste your JSON data into the input area
Paste your JSON data into the input area. Follow the tool interface to complete this step.
tool automatically validates syntax and shows errors if any exist
The tool automatically validates syntax and shows errors if any exist. Follow the tool interface to complete this step.
For formatting, click 'Format' to beautify with proper indentation
For formatting, click 'Format' to beautify with proper indentation. Follow the tool interface to complete this step.
For minification, click 'Minify' to remove all unnecessary whitespace
For minification, click 'Minify' to remove all unnecessary whitespace. Follow the tool interface to complete this step.
Review validation results
green check for valid, red error for invalid JSON
If errors exist, check the error message for exact line and issue description
If errors exist, check the error message for exact line and issue description. Follow the tool interface to complete this step.
Fix errors, and the tool revalidates automatically
Fix errors, and the tool revalidates automatically. Follow the tool interface to complete this step.
Copy the formatted or minified JSON with one click
Copy the formatted or minified JSON with one click. Follow the tool interface to complete this step.
Frequently Asked Questions
What are the most common JSON syntax errors?
Common errors include: trailing commas after the last element (not allowed in JSON), using single quotes instead of double quotes for strings, forgetting commas between elements, unclosed brackets or braces, unquoted keys (keys must be in double quotes), and using undefined, NaN, or Infinity (not valid JSON values).
What's the difference between JSON and JavaScript objects?
JSON is a text format with strict rules: keys must be double-quoted strings, only double quotes for strings, no trailing commas, no comments, no functions, no undefined. JavaScript objects are more flexible: can use single quotes, trailing commas allowed, can have comments, functions, and undefined. JSON is a subset of JavaScript literal notation.
Can JSON contain comments?
No, standard JSON does not support comments. This is by design for simplicity and interoperability. If you need comments in configuration files, consider JSON5 or JSONC (JSON with comments) formats, or use a different format like YAML. Some parsers accept comments as an extension, but they're not standard.
Why does my JSON validation fail with 'unexpected token'?
'Unexpected token' usually means a character that shouldn't be there. Common causes: trailing comma, single quotes instead of double quotes, missing comma between elements, extra bracket or brace, or special characters not properly escaped. Our validator shows the exact location to help fix it.
How do I handle special characters in JSON strings?
Escape special characters with backslash: " for quotes, \\ for backslash, \n for newline, \t for tab, \r for carriage return. Unicode characters can use \uXXXX notation. For example: "He said \"Hello\"" or "Line 1\nLine 2". Our tool handles escaping automatically.
Should I minify JSON for production?
For APIs and web services where JSON is transmitted over networks, minification reduces bandwidth and improves performance by removing whitespace. However, for configuration files that humans edit, keep it formatted for readability. Minify JSON served to users, format JSON edited by developers.
Can JSON represent all data types?
JSON supports: strings, numbers, booleans (true/false), null, arrays, and objects. It does NOT support: dates (use ISO 8601 strings), functions, undefined, NaN, Infinity, comments, or binary data (use Base64 encoding). Convert unsupported types to supported ones before JSONifying.
What is JSON Schema and why use it?
JSON Schema defines the structure, data types, and validation rules for JSON data. It's like a contract specifying required fields, data types, value ranges, and formats. Use it for API contract validation, ensuring data quality, documenting expected JSON structure, and automated testing of JSON payloads.
Use Cases
- API Development and Testing: Validate API request payloads before sending, format API responses for readability, debug malformed JSON from endpoints, and create test data with proper JSON structure.
- Configuration File Management: Create and validate JSON config files for applications, package.json for Node.js projects, settings.json for editors, and any JSON-based configuration with guaranteed valid syntax.
- Data Analysis and Transformation: Format exported JSON data for analysis, validate data before import into databases, clean up JSON from web scraping, and prepare data for visualization tools.
- Learning and Teaching JSON: Students learning JSON can validate their work, understand error messages, see proper formatting examples, and develop good JSON writing habits with instant feedback.
- Code Review and Documentation: Format JSON examples for documentation, code reviews, and README files. Ensure all JSON snippets in documentation are valid and properly formatted for clarity.