JSON to TypeScript

Paste sample JSON and generate TypeScript interfaces with nested types in seconds.

Root interface name:

JSON Input

TypeScript Interfaces

Interfaces from real JSON samples

Guessing types from documentation is slow and error-prone. CalcForge inspects your JSON payload and emits TypeScript interfaces that mirror actual keys, arrays, and nullable fields—ready to drop into front-end apps or shared packages.

Good fits

Typing REST responses before OpenAPI specs catch up
Bootstrapping React or Node projects from example webhooks
Creating shared DTO types from production log samples (redacted)
Teaching structural typing from concrete API data

JSON:
{"user":{"id":1,"roles":["admin","editor"]}}

TypeScript:
interface Root {
  user: {
    id: number;
    roles: string[];
  };
}

Practical notes

One sample may not show every variant—merge types when optional fields appear in other responses.
Rename root interfaces to match your domain (`ApiResponse`, `UserProfile`).
Pair with JSON Schema Generator when you need runtime validation too.

Related CalcForge tools

Frequently asked questions

Are optional fields detected automatically?

Missing keys in one sample become required in output. Feed multiple examples or mark optionals manually after generation.

Does it handle null and union types?

Null values infer nullable types. Mixed scalar types in one array may become union types—review before committing.

Can I export type aliases instead of interfaces?

Output style depends on generator settings. Adjust naming and switch to interfaces vs types in your editor as needed.

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