Convert JSON payloads to clean TypeScript interfaces and type definitions instantly. Supports nested objects, optional keys, and union types. Free tool.
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JSON to TypeScript analyzes raw JSON data structures and automatically generates strongly typed TypeScript interfaces, type aliases, and nested object types with inferred primitives and optional fields. Convert JSON to TypeScript interface definitions instantly in your browser.
Recursively traverses the input JSON object graph, inferring scalar types (string, number, boolean, null) and composite array/object types. It names nested sub-interfaces automatically using camelCase/PascalCase heuristics and unifies heterogeneous array types into union types (e.g., `(string | number)[]`).
{
"id": 101,
"username": "sarah_dev",
"isActive": true,
"tags": ["frontend", "react"]
}export interface UserProfile {
id: number;
username: string;
isActive: boolean;
tags: string[];
}Maps scalar keys to strict TypeScript primitive types and array elements to typed string arrays.
Paste your JSON data into the editor and specify a root interface name. The tool parses the keys, infers primitive types, handles optional properties, and generates strongly typed TypeScript interfaces with nested type declarations ready to copy.
Yes, the engine deeply traverses the JSON structure. If it encounters a nested object or array of objects, it will automatically extract them and create dedicated sub-interfaces.
If a JSON array contains both strings and numbers, the tool will intelligently infer a union type (e.g., string | number) to ensure maximum type safety.
Absolutely. The conversion logic runs entirely locally in your browser. We never log or transmit your proprietary data structures to any backend server.