JSON to TypeScript Interfaces

Convert JSON data into TypeScript interface definitions with nested object and array type inference

Interface name

Use type instead of interfaceMake all properties optional (?)

JSON Input

TypeScript Output

TypeScript Output

Documentation

About JSON to TypeScript

This tool converts JSON sample data into TypeScript type definitions for API modeling, mock constraints, and editor autocomplete.

Key Features

Automatic Type Inference: Infers primitives, arrays, and object structures.
Interface or Type Alias: Choose output style (interface or type).
Optional Property Control: Generate optional fields when needed.
Custom Root Name: Set root type name and export as .ts.

Steps

Paste valid JSON into input.
Configure root type name and generation options.
Convert and review TypeScript output.
Copy or download generated code.

Recommendations

Use realistic API payload samples for better type quality.
Refine union-heavy outputs manually for readability.
Keep critical fields required whenever possible.

FAQ

Why are some fields inferred as union types?

When the same field has different value types across items, the tool merges them into unions.

Does it support array roots?

Yes. It generates element-related definitions and a typed root export.