Schema names (OpenAPI) | Fern Documentation

OpenAPI allows you to define inlined schemas that do not have names.

Inline type in openapi.yml

components:
  schemas:
    Movie:
      type: object
      properties:
        name:
          type: string
        cast:
          type: array
          items:
            type: object
            properties:
              firstName:
                type: string
              lastName:
                type: string
              age:
                type: integer

Fern automatically generates names for all the inlined schemas. For example, in this example, Fern would generate the name CastItem for the inlined array item schema.

Auto-generated name

export interface Movie {
  name?: string;
  cast?: CastItem[];
}
export interface CastItem {
  firstName?: string;
  lastName?: string;
  age?: integer;
}

If you want to override the generated name, you can use the extension x-fern-type-name.

openapi.yml

components:
  schemas:
    Movie:
      type: object
      properties:
        name:
          type: string
        cast:
          type: array
          items:
            type: object
            x-fern-type-name: Person
            properties:
              firstName:
                type: string
              lastName:
                type: string
              age:
                type: integer

This would replace CastItem with Person and the generated code would read more idiomatically:

Overridden name

export interface Movie {
  name?: string;
  cast?: Person[];
}
export interface Person {
  firstName?: string;
  lastName?: string;
  age?: integer;
}