As we've seen different rules for URIs in general, we will discuss the authority (scheme "://" authority "/" path [ "?" query ] [ "#" fragment ]) portion of the REST API URI:

• Use consistent sub-domain names:
  • Consistent sub-domain names for an API include the following:
    • The top-level domain and the first sub-domain names indicate the service owner and an example could be baseball.restfulapi.org
    • As you see in http://api.baseball.restfulapi.org, the API domain should have api as part of its sub-domain
  • Consistent sub-domain names for a developer portal  include the following:
    • As we saw in the API playgrounds section, the API providers should have exposed sites for APP developers to test their APIs called a developer portal. So, by convention, the developer portal's sub-domain should have developer in it. An example of a sub-domain with the developer for a developer portal would be http://developer.baseball.restfulapi.org.