Are namespaces required in Apex REST endpoint URLs?

In the context of Apex REST services, namespaces play a critical role, especially when it comes to ensuring that the endpoints are uniquely identifiable across different packages. When a managed package is created, it contains a unique namespace that distinguishes its components from those in other packages or orgs.

For organizations that have MyDomain enabled, the use of namespaces in Apex REST endpoint URLs becomes necessary to ensure that there are no conflicts with other packages or standard Salesforce components. Therefore, when you create an Apex REST service in an org with MyDomain enabled and you are using a managed package, you must include the namespace in the URL to correctly direct requests to the appropriate Apex class.

Furthermore, even in unmanaged packages that leverage MyDomain, it is good practice to use namespaces to maintain consistency and avoid potential naming conflicts.

This is why the correct answer indicates that namespaces are indeed required for both managed and unmanaged packages when MyDomain is enabled. It highlights the importance of maintaining clarity and avoiding conflicts within the Salesforce ecosystem.