JSON to TypeScript Converter - Generate TS Interfaces Online

Online JSON to TypeScript Converter: Generate Precise Types Instantly

Stop wasting time manually writing interfaces for your API responses. Our JSON to TypeScript converter is a powerful tool designed to transform raw JSON data into clean, production-ready TypeScript interfaces or type aliases. Whether you are working on a React, Angular, or Vue project, this tool helps you maintain strict type safety and a robust codebase with zero effort.

Why Convert JSON to TypeScript?

TypeScript's core strength is its ability to define data shapes, but manually mapping complex API payloads is a common developer bottleneck.

Boost Development Productivity

Instead of spending 10 minutes manually typing out nested properties and trying to guess if a value is optional, you can paste your JSON here and get the job done in seconds. This allows you to focus on building features rather than writing boilerplate interfaces.

Enhance Type Safety and IntelliSense

By using accurate TypeScript interfaces generated from real data, your IDE (like VS Code) can provide perfect autocompletion and highlight potential errors before you even run your code. This significantly reduces the risk of "undefined is not a function" errors at runtime.

Key Features of Our JSON to TypeScript Tool

Our converter is built with the needs of professional developers in mind, offering more than just basic string mapping.

1. Intelligent Type Inference

The engine analyzes your values to determine the best TypeScript representation:

• Strings and Numbers: Maps to string or number.

• Booleans: Maps to boolean.

• Null Values: Automatically suggests any or null | string.

• Arrays: Generates specific array types like string[] or Array<User>.

2. Recursive Interface Generation

When your JSON contains nested objects, our tool doesn't just create one giant, unreadable block. It recursively generates separate, named interfaces for each sub-object. This modular approach makes your code cleaner and allows you to reuse sub-types across your application.

3. Support for Optional Properties

Our tool can detect if fields appear inconsistently in an array of objects and automatically mark them as optional using the ? operator (e.g., id?: number;). This reflects real-world API behavior where not all fields are always present.

How to Convert JSON to TypeScript

1. Paste your JSON: Insert your raw JSON response or object into the input area.

2. Naming: (Optional) Provide a root name for your interface (e.g., RootObject or UserResponse).

3. Instant Conversion: The tool generates the TypeScript code immediately.

4. Copy and Use: Click "Copy to Clipboard" and paste the code directly into your .ts or .tsx file.

Technical Insights: Clean TypeScript Standards

Interfaces vs. Types

By default, our tool generates Interfaces because they are better for performance and allow for "declaration merging" in large-scale projects. However, you can easily toggle to Type Aliases depending on your project's coding style.

Handling Deep Nesting

Unlike basic converters that produce "inline" nested types, we prioritize a "flattened" structure. This means nested objects get their own named interfaces, making your code easier to read and much simpler to document with JSDoc.

Frequently Asked Questions (FAQ)

Is this tool compatible with TypeScript 5.x?

Yes! The generated code follows standard TypeScript syntax compatible with all modern versions, including the latest 5.x releases.

Does it support BigInt or Date types?

The tool maps large numbers to number and ISO strings to string by default. You can manually adjust these to BigInt or Date based on your specific implementation needs.

Is my data secure?

Absolutely. Your data privacy is our priority. All conversion logic happens 100% locally in your browser using JavaScript. No JSON data is ever sent to or stored on our servers.