Why convert JSON to TypeScript?

It helps you create safer front-end and API code by turning sample payloads into typed models.

Should I use interfaces or type aliases?

Either can work. Interfaces are familiar for object shapes, while type aliases are flexible for unions and quick generated output.

Fix the JSON first with a validator, then generate the TypeScript definitions.

Use the JSON to TypeScript page.

Take a representative JSON payload rather than the smallest possible sample. The better your example, the more useful the generated types will be.

{
  "id": 1,
  "name": "Ada",
  "active": true
}

That payload can become:

export type Root = {
  id: number;
  name: string;
  active: boolean;
};

If arrays mix multiple shapes, or if optional properties are missing from the sample, you may need to refine the generated output by hand.

FAQ

Can I convert arrays of objects?

Yes. Arrays are supported and can generate array types or unions.

Will optional fields always be inferred?

Only if the sample reflects that variability. Generated types are only as complete as the example payload.

Should I validate first?

Yes. Invalid JSON should be fixed before you generate TypeScript.

Is this useful for API clients?

Very much so. It is one of the quickest ways to scaffold typed client models.