with RestyGWT you can work with external rest services

[Carlos Alberto Borda Benito]

GWT as a user I'm thinking of using RestyGWT to consume external services that are not within the same project, in other words are third party services.

[christian]

yes RestyGWT can, might need CORS setup or so if they run on different servers.

[Ignacio Baca Moreno-Torres]

Maybe you are interested in this alternative approach, AutoREST (https://github.com/intendia-oss/autorest-gwt), which was inspired by RestyGWT but with a different approach. Checkout this example, this is how you define the thirdparty API (https://github.com/ibaca/autorest-nominatim-example/blob/master/api/src/main/java/com/intendia/gwt/example/client/Nominatim.java), in this case nominatim reverse geolocation service. And this is how it's used in GWT (https://github.com/ibaca/autorest-nominatim-example/blob/master/gwt/src/main/java/com/intendia/gwt/example/client/ExampleEntryPoint.java), also usable in JRE client, JRE as service and android.

RestyGWT is a much more mature project, but if you are investigating options, this project might be interesting. Also it uses APT instead of generators, so you can see the generated code in your IDE. Also, all the generated code is not GWT dependant, so you can define your third party service and tests it using JRE instead of GWT.