Which feature allows you to create an API version without affecting the existing applications?

Creating an API version without impacting existing applications is a critical capability in API management and design. Versioning is the feature that facilitates this by allowing developers to introduce changes, enhancements, or fixes to an API without disrupting the functionality of applications that depend on earlier versions.

When a new version of an API is released, it can coexist with the previous version, enabling clients to choose which version to use according to their needs. This approach minimizes the risk of breaking changes affecting ongoing operations and provides a smoother transition path for clients that may need time to adapt to the changes.

In contrast, schema validation ensures that the data conforms to certain structures but does not inherently govern how different API versions are managed. Authentication secures access to APIs but does not relate to version control. Deployment refers to the process of making an API operational, which also does not involve the management of versions. Hence, versioning stands out as the essential feature that enables API evolution while maintaining compatibility with existing clients.