diff --git a/server/request_handler.go b/server/request_handler.go
index 2cb994c..6c2fd85 100644
--- a/server/request_handler.go
+++ b/server/request_handler.go
@@ -117,7 +117,8 @@ func (r *RpcRequestHandler) process() {
 	if ok && len(customProxyUrl[0]) > 1 {
 		metrics.UrlParamUsageInc()
 		r.defaultProxyUrl = customProxyUrl[0]
-		r.logger.Info("[process] Using custom url", "url", r.defaultProxyUrl)
+		originID := r.req.Header.Get("X-Flashbots-Origin")
+		r.logger.Info("[process] Using custom url", "url", r.defaultProxyUrl, "originID", originID)
 	}
 
 	// Decode request JSON RPC
diff --git a/server/server.go b/server/server.go
index 564732c..7beb398 100644
--- a/server/server.go
+++ b/server/server.go
@@ -344,5 +344,5 @@ func (s *RpcEndPointServer) HandleBundleRequest(respw http.ResponseWriter, req *
 
 func setCorsHeaders(respw http.ResponseWriter) {
 	respw.Header().Set("Access-Control-Allow-Origin", "*")
-	respw.Header().Set("Access-Control-Allow-Headers", "Accept,Content-Type")
+	respw.Header().Set("Access-Control-Allow-Headers", "Accept,Content-Type,X-Flashbots-Origin")
 }