diff --git a/lib/server.js b/lib/server.js
index 7da2c47..3936d41 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -133,6 +133,14 @@ Barnacles.prototype.addService = function(options) {
   }
 }
 
+/**
+ * Add a service instance to notify. This brings more flexibility to insert any service from the callsite.
+ * @param {String} name A name to identify the service on the list of services.
+ * @param {Object} service A instance of a customized service.
+ */
+Barnacles.prototype.addServiceInstance = function(name, service) {
+    this.services[name] = service;
+}
 
 /**
  * Get the current state of events.