How do custom media types improve API versioning in REST?

1 URI changes

One of the benefits of using custom media types is that they reduce the need for changing the URI of the resources. Instead of adding version numbers or suffixes to the URI, such as /users/v1 or /users.json, you can use the Accept and Content-Type headers to specify the desired media type, such as application/vnd.example.user-v1+json or application/vnd.example.user-v2+xml. This way, you can preserve the uniformity and stability of the URI, which is a good practice for RESTful design.

3 Documentation and discoverability

A third benefit of using custom media types is that they improve the documentation and discoverability of the API. By using custom media types, you can provide clear and consistent information about the available representations of the resources, their structure, and their semantics. For example, you can use the media type name to indicate the version, the domain, and the format of the resource, such as application/vnd.example.user-v3+json. You can also use the Link header to provide links to related resources or actions, such as self, edit, or delete. This way, you can help the clients to understand and navigate the API.

4 Pitfalls avoidance

Using custom media types offers a final benefit, as it allows you to avoid the pitfalls of other versioning strategies, such as URI versioning which violates the principle of resource identification, query parameter versioning which pollutes the query string and makes caching difficult, and header versioning which requires custom headers and may conflict with standard headers. Custom media types enable you to leverage the existing content negotiation mechanism, thus avoiding these issues.

5 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?