If your module is correctly implementing interfaces and preferences for them in its di.xml then enabling web API access to your object’s repository should look something like the example shown below. You have the option of setting an ACL resource on any particular endpoint or making it publicly accessible for unauthenticated usage (maybe on the frontend of your site via AJAX?).
File Location: app/code/Vendor/Module/etc/webapi.xml
No syntax highlighting on this one. Not sure which part of this liked me trying to post XML the least…but that’s added to the backlog now! Thankfully < XMP > hasn’t been removed yet!