Optional Parameters in Web API Attribute Routing and Default Values: You can make a URI parameter as optional by adding a question mark (“?”) to the route parameter . If you make a route parameter as optional then you must specify a default value by using parameter = value for the method parameter.
What are optional parameters in API?
Optional Parameters in Web API Attribute Routing and Default Values: You can make a URI parameter as optional by adding a question mark (“?”) to the route parameter . If you make a route parameter as optional then you must specify a default value by using parameter = value for the method parameter.