Types

A schema is a tree of nodes: the schema itself, each property of an object, and the items of an array or the values of a map, as in Pet and Pets:

schemas:
  Pet:
    type: object
    properties:
      petId:
        type: integer
      name:
        type: string
      nickname:
        type: string
        optional: true
  Pets:
    type: array
    items:
      ref: Pet

Types and their keys#

A node's type is object, array, map or one of the primitives string, integer, float, number and boolean; any other value is rejected at publish. Every node declares type, except a node that is a ref (References). A node with neither is rejected at publish, even when its items or properties already show what it is:

Pet:
  type: object
  properties:
    tags:
      items:
        type: string

contract validation failed
  - petstore_api.yaml: missing "type" at schemas Pet properties tags, expected one of: object, array, map, string, integer, float, number, boolean

Each type takes only its own keys:

A key on the wrong type is rejected at publish, and the line names the type it belongs to:

Pet:
  type: object
  properties:
    tags:
      type: string
      items:
        type: string

contract validation failed
  - petstore_api.yaml: "items" is not allowed on a string schema at schemas Pet properties tags, use it with "type: array"

Any node may also carry description, free text that the broker ignores (What is not compared).

Primitives#

integer and float are strict: a consumer that declares float where the provider declares integer is a type mismatch. number is for a value that JSON sends as 50 or 50.5 alike, on either side. A reader writes it when its code accepts both. A producer writes it when its value can be a round float: PHP's json_encode sends the float 50.0 as 50, so that value is number, not float or integer. A number reader accepts all three, and a number producer breaks a strict reader. The producer and the reader of a body are in Which side decides:

Two modules of the same consumer that declare number and integer for the same property are still rejected as different types (Several files).