Use name@provider instead of provider@name.

pkg/api/testdata/routers.json

@@ -5,12 +5,12 @@
 		],
 		"middlewares": [
 			"auth",
-			"anotherprovider@addPrefixTest"
+			"addPrefixTest@anotherprovider"
 		],
-		"name": "myprovider@bar",
-		"provider": "myprovider@bar",
+		"name": "bar@myprovider",
+		"provider": "myprovider",
 		"rule": "Host(`foo.bar`)",
-		"service": "myprovider@foo-service"
+		"service": "foo-service@myprovider"
 	},
 	{
 		"entryPoints": [
@@ -20,9 +20,9 @@
 			"addPrefixTest",
 			"auth"
 		],
-		"name": "myprovider@test",
-		"provider": "myprovider@test",
+		"name": "test@myprovider",
+		"provider": "myprovider",
 		"rule": "Host(`foo.bar.other`)",
-		"service": "myprovider@foo-service"
+		"service": "foo-service@myprovider"
 	}
 ]