JSON to TypeScript Interface Generator - Convert JSON to TS Types | FreeFormatHub

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JSON Data

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Syntax: json

📋 Quick Examples

Generated Interface Preview

export interface GeneratedInterface { ... }

This will be the main interface name in your generated TypeScript code

TypeScript Tips

💡 Best Practices

• Optional Properties: Use when data might be incomplete

• Union Types: Handle arrays with mixed types

• CamelCase: Convert API snake_case to JS convention

• Export Interfaces: Enable imports in other modules

Output

Output will appear here

How It Works

Input Your Data

Paste, type, or upload your data directly into the json to typescript interface. All processing happens locally in your browser for complete privacy and security.

Configure Options

Customize the tool settings to match your specific needs. Real-time processing with instant validation and error detection.

Process Instantly

Click the process button or enable auto-processing for real-time results. Lightning-fast performance with immediate feedback and validation.

Export Results

Copy results to clipboard, download as files, or share with others. Multiple export formats available for maximum compatibility.

Frequently Asked Questions

How does it handle arrays with different item types?

With "Infer Array Types" enabled, it creates union types like (string | number)[] for mixed arrays. It can also generate separate interfaces for object arrays.

What about optional properties?

Enable "Optional Properties" to mark properties with null/undefined values as optional (property?: type). This makes interfaces more flexible for incomplete data.

Can it handle deeply nested objects?

Yes, it automatically generates separate interfaces for nested objects and references them properly. Each nesting level gets its own interface definition.

How does it handle invalid property names?

Properties with spaces or special characters are automatically quoted ("property name": type). Enable camelCase conversion for cleaner property names.

What about null values and undefined?

Enable "Include Nullables" to preserve null types, or disable it to convert null values to "any" type for more permissive interfaces.