diff --git a/extractor.go b/extractor.go
index 10ce4db..f844ddf 100644
--- a/extractor.go
+++ b/extractor.go
@@ -43,6 +43,7 @@ func serviceDef(opts server.Options) *registry.Service {
 	node.Metadata["server"] = "http"
 	node.Metadata["broker"] = opts.Broker.String()
 	node.Metadata["registry"] = opts.Registry.String()
+	node.Metadata["protocol"] = "http"
 
 	return &registry.Service{
 		Name:    opts.Name,