Hi Nathan,

Yes this is possible. There is a good tutorial here. https://our.umbraco.com/documentation/reference/routing/webapi/

Look at the bottom... Using MVC Attribute Routing in Umbraco Web API Controllers

Basically add these two classes to your project

 public class AttributeRoutingComponent : IComponent
    {
        public void Initialize()
        {
            GlobalConfiguration.Configuration.MapHttpAttributeRoutes();

        }

        public void Terminate()
        {

        }
    }

    [RuntimeLevel(MinLevel = RuntimeLevel.Run)]
    public class AttributeRoutingComposer : IComposer
    {
        public void Compose(Composition composition)
        {
            composition.Components().Insert<AttributeRoutingComponent>(); ;
        }
    }

Then your API Method might look something like this..

 [HttpGet]
        [Route("residence/api/getall")]
        public TestDataDto GetAll()
        {
            TestDataDto TestDataDto = new TestDataDto();
            TestDataDto.TestString = "this is a test";
            TestDataDto.AnotherTestString = "this is a another test";
            TestDataDto.TestInt = 99;
            TestDataDto.TestBool = true;
            return TestDataDto;
        }

Regards

David