Options

All adapterOas options are optional. Types and defaults are listed below.

Options overview

Option details

validate

Validates the OpenAPI spec with @readme/openapi-parser before parsing. Each problem is reported as a KUBB_INVALID_SPEC warning, and generation continues. Set it to false to skip the check, which makes generation faster on a large spec. Run kubb validate to list every error.

contentType

Preferred media type when an operation defines several. Without a value, Kubb falls back to the first JSON-like media type in the spec (application/json, application/x-json, text/json, text/x-json, or any *+json), and to the first media type overall when none is JSON-like.

server

Selects which entry in the spec's servers array Kubb resolves into the document baseURL, filling in any {variable} placeholders. server.index points at one of the spec's servers, usually 0 for the primary one. server.variables supplies placeholder values, falling back to each variable's default from the spec. Omit server and baseURL resolves to null.

The resolved baseURL reaches banner functions through BannerMeta.baseURL but does not set request URLs on its own. To change where a generated client sends requests, use that plugin's own baseURL option (@kubb/plugin-fetch, @kubb/plugin-axios, @kubb/plugin-msw).

With a spec server of https://api.{env}.example.com, server: { index: 0, variables: { env: 'prod' } } resolves baseURL to https://api.prod.example.com.

discriminator

How discriminator fields on oneOf/anyOf schemas are interpreted.

openapi: 3.0.3
components:
  schemas:
    Animal:
      required: [type]
      type: object
      oneOf:
        - $ref: '#/components/schemas/Cat'
        - $ref: '#/components/schemas/Dog'
      discriminator:
        propertyName: type
        mapping:
          cat: '#/components/schemas/Cat'
          dog: '#/components/schemas/Dog'
    Cat:
      type: object
      properties:
        type: { type: string }
        indoor: { type: boolean }
    Dog:
      type: object
      properties:
        type: { type: string }
        name: { type: string }

export type Cat = { type: string; indoor?: boolean }
export type Dog = { type: string; name?: string }
export type Animal = Cat | Dog

export type Cat = { type: 'cat'; indoor?: boolean }
export type Dog = { type: 'dog'; name?: string }
export type Animal = Cat | Dog

enums

Where inline enums live.

For an enum with values active and inactive on Pet.status:

export type Pet = { status?: 'active' | 'inactive' }

export type PetStatusEnum = 'active' | 'inactive'
export type Pet = { status?: PetStatusEnum }

dateType

How date-time, date, and time schemas are represented downstream.

Pass a single value to apply it to all three formats:

The string variants all emit string at the TypeScript type level. The offset and local distinction surfaces in schema output such as Zod.

Pass an object to set dateTime, date, and time independently. A key you leave out defaults to 'string', regardless of the other keys.

adapterOas({
  dateType: {
    dateTime: 'date', // Date object for timestamps
    date: 'string', // plain string for date-only values, since Date can't represent them safely
    time: 'string',
  },
})

integerType

How type: integer (and format: int64) maps to TypeScript.

This option only applies to schemas that declare a numeric type. A schema that declares type: string stays a string whatever its format, so the { type: 'string', format: 'int64' } that gRPC-gateway and other ProtoJSON producers emit generates a string. @kubb/plugin-zod validates those fields with a digits .regex(...) and @kubb/plugin-faker mocks them with a numeric string.

unknownType

AST type used when a schema's type cannot be inferred from the spec (additionalProperties: true, a missing type, and similar).

emptySchemaType

AST type used for fully empty schemas ({}). It follows unknownType unless you set it. Override it only when empty schemas should be treated differently from unresolvable ones.

enumSuffix

Suffix appended to derived enum names when Kubb has to invent one, typically for inline enums on object properties. The derived name joins the parent schema name, the property name, and the suffix in PascalCase, so an inline enum on the status property of the Pet schema derives PetStatusEnum. Set it to 'type' and the same enum derives PetStatusType.