How does it handle nested objects?

Nested objects generate separate named interfaces. Arrays are typed based on their contents — if all items have the same shape, a single interface is generated.

Does it handle optional fields?

If analyzing a single JSON object, all fields are required. For arrays of objects where some items have missing keys, those fields are marked optional with ?.

Can I customize the root type name?

Yes — enter a custom name for the root interface.

JSON to TypeScript

Generate TypeScript interfaces and types from JSON data. Paste JSON, get type-safe TypeScript instantly.

Root interface name

JSON

TypeScript

Frequently asked questions

JSON to TypeScript — Generate Interfaces Online Free

Paste any JSON and instantly get TypeScript interfaces with proper typing. Handles nested objects, arrays, nullables, and optional fields.

Deep nesting

Nested objects and arrays get their own named interfaces.

Accurate types

Detects strings, numbers, booleans, nulls, arrays, and nested objects.

Copy & use

Copy the generated types directly into your TypeScript project.