Field guide / Generate types

Real JSON.Useful types.

Turn sample data into TypeScript, Zod or JSON Schema.

THE WORKFLOW, AT A GLANCE

Start with this sample

JSON sample

1[
2  { "id": 1, "name": "Ada" },
3  { "id": "2" }
4]

Generated TypeScript

1export interface RecordItem {
2  id: number | string;
3  name?: string;
4}

Worth knowing

Review unusual identifiers, mixed arrays and nullability in other targets. Generating JSON Schema creates a schema; it does not validate against an existing one.

Follow the steps

01
Use a representative sample
Include nulls, optional fields and mixed records. TypeScript, Zod and JSON Schema inspect every supplied array member.
02
Pick your output
Open Generate types and choose a target. The preview updates for TypeScript, Zod, JSON Schema and eight additional language targets.
03
Make the names yours
For TypeScript, expand a declaration and use the pencil to rename it, for example RecordItem. Fields can be renamed; declarations can be reordered.
04
Copy, then check
Use Copy Code and check it in your project. Samples cannot cover every production case; the eight additional targets use simpler inference.

Try it in FyJSON

Real JSON.Useful types.

Use a representative sample

Pick your output

Make the names yours

Copy, then check

Real JSON.Useful types.

Use a representative sample

Pick your output

Make the names yours

Copy, then check