JSONLint

Validator and Formatter

Free JSON Validator, Formatter & Type Generator

Validate JSON syntax, format messy JSON data, and automatically generate strongly-typed code for TypeScript, Go, Python, Java, and C#. Perfect for developers working with APIs, configuration files, and data structures.

Simply paste your JSON below to get started:

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About JSONLint - The Complete JSON Tool

JSON ValidationAuto FormattingTypeScript TypesGo StructsPython ClassesJava ClassesC# Classes

JSONLint is a comprehensive JSON validator, formatter, and type generator that helps developers work more efficiently with JSON data. Whether you're debugging API responses, cleaning up configuration files, or generating type definitions for your applications, JSONLint provides all the tools you need in one place. Our advanced JSON editor features real-time syntax highlighting, error detection, and automatic code generation for popular programming languages.

Why Choose JSONLint?

🚀 Fast & Reliable

Instant JSON validation and formatting with real-time error detection. No server roundtrips needed.

🔧 Developer-Friendly

Generate type definitions for TypeScript, Go, Python, Java, and C# from your JSON data automatically.

🎨 Syntax Highlighting

Beautiful code highlighting with line numbers, folding, and smart indentation for better readability.

📱 Always Available

Works offline, mobile-friendly, and completely free. No registration or API keys required.

How to Use

1
Input JSON: Paste or type your JSON code in the editor above. The editor provides syntax highlighting and real-time validation.
2
Validate & Format: Click "Validate JSON" or press Ctrl+Enter (or Cmd+Enter on Mac) to validate and auto-format your JSON.
3
Generate Types: Automatically generate type definitions for TypeScript, Go, Python, Java, or C# from your validated JSON.
4
Copy & Use: Copy the formatted JSON or generated types to your clipboard with one click and use them in your projects.

Keyboard Shortcuts

Validate JSONCtrl+Enter
Auto-format JSONCtrl+F
Indent line(s)Tab
Unindent line(s)Shift+Tab

Complete Feature Set

Real-time syntax highlighting
Automatic indentation & formatting
JSON validation with detailed errors
TypeScript interface generation
Go struct generation
Python dataclass generation
Java class generation
C# class generation
One-click copy to clipboard
Auto-format on paste
Keyboard shortcuts support
Line numbers & code folding
Mobile responsive design
Works completely offline
No registration required

Perfect for Developers

Whether you're working with REST APIs, GraphQL responses, configuration files, or database exports, JSONLint streamlines your JSON workflow. Generate type-safe code for your favorite programming language and catch JSON errors before they become runtime bugs. Used by thousands of developers worldwide for API development, data migration, and code generation.