OpenAPI Specification 3.0 support - Cloud

Talend Cloud API Designer User Guide

Talend Cloud
Talend API Designer
Design and Development > Designing APIs
Last publication date
Design an API with OpenAPI Specification (OAS) 3.0 using Talend Cloud API Designer.

OpenAPI Specification 3.0 comes with new features, bringing more expressivity and productivity to API designers.

For more information about OpenAPI, see the Swagger documentation.


Components allow you to reuse various elements across an API. These elements can be:
  • Path variables
  • Query parameters
  • Headers
  • Responses


Combinations allow you to create a new data type by combining several other data types. Talend Cloud API Designer supports two types of combinations:
  • Composition (allOf) allows you to aggregate schema properties from different schemas. For example, you can define a data type anatomy by reusing all the properties from the existing types nervousSystem, skeleton and digestiveSystem.
  • Polymorphism (oneOf /anyOf) allows you to to create an entity that can use the properties from different data types.
    • oneOf allows you to define a data type containing the properties of one of the selected types. For example, if you create an operation to get information about an organ, you can define the response using the oneOf combination to get either all the properties of brain or all the properties of heart.
    • anyOf allows you to define a data type containing the properties of one or several of the selected types. For example, you can define a data type nervousSystem and a type skeleton containing different properties, and use the anyOf combination to create a data type containing any properties from either of these types.

      An anyOf combination is valid as long as it contains all the required parameters of at least one of the data types selected. The example below uses the brain_weight property from the nervousSystem type and the skull_height and teeth properties from skeleton.

For more information about composition and polymorphism, see Inheritance and Polymorphism and Difference Between anyOf and oneOf.


OAS 3.0 allows you to define new types of responses for your operations:
  • Response ranges: instead of defining a response such as 200, you can set it as 2XX, so that it includes responses from 200 to 299.
  • Default responses: you can define a default response to be returned when a specific or range response is not defined.
Responses defined with an explicit code take precedence over response ranges and default responses, and response ranges take precedence over default responses. In the following example:
  • The 204 response is defined and takes precedence over the others.
  • The 2XX response applies to response codes 200 to 203 and 205 to 299.
  • The default response applies to all 1XX, 3XX, 4XX and 5XX responses.


OAS 3.0 brings new security schemes for your API:
  • Bearer authentication
  • OpenIdConnect


OAS 3.0 allows you to indicate that some properties are read-only or write-only.

This option is available in data types only and cannot be defined in requests or responses at the operation level.