diff --git a/rest/RESTCallBack.cpp b/rest/RESTCallBack.cpp
index e6eca15..0b91fbb 100644
--- a/rest/RESTCallBack.cpp
+++ b/rest/RESTCallBack.cpp
@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <iostream>
 #include "RESTCallBack.h"
 
 RESTCallBack::~RESTCallBack()
@@ -27,6 +28,16 @@ void RESTCallBack::getDescription(Dumais::JSON::JSON& json)
 RESTEngine::ResponseCode RESTCallBack::call(Dumais::JSON::JSON& json, const std::string& paramString, const std::string& dataString, std::smatch& matches)
 {
     RESTParameters params(paramString, mParamList);
+    // Let's check mandatory/required params
+    for (ParamMap::const_iterator it = mParamList.begin(); it != mParamList.end(); ++it) {
+        if (it->second.mRequired) {
+            if (params.getParam(it->first).empty()) {
+                std::cerr << "Missing mandatory parameter " <<  it->first << std::endl;
+                // todo : replace empty parameter value by default parameter value
+            }
+        }
+    }
+
     RESTEngine::ResponseCode responseCode = RESTEngine::ResponseCode::OK;
     RESTContext context ={
         json,
diff --git a/rest/RESTEngine.h b/rest/RESTEngine.h
index 823235f..7635780 100644
--- a/rest/RESTEngine.h
+++ b/rest/RESTEngine.h
@@ -26,8 +26,14 @@ class RESTEngine{
     enum ResponseCode
     {
         OK,
+        Created,
+        Accepted,
+        BadRequest,
+        Forbidden,
         NotFound,
-        MethodNotAllowed
+        MethodNotAllowed,
+        NotImplemented,
+        ServiceUnavailable
     };
 
     RESTEngine();
diff --git a/rest/RESTParameters.cpp b/rest/RESTParameters.cpp
index 3297dc2..3afc258 100644
--- a/rest/RESTParameters.cpp
+++ b/rest/RESTParameters.cpp
@@ -43,6 +43,7 @@ RESTParameters::RESTParameters(const std::string &params, const ParamMap &regist
             break;
         }
     }
+
 }
 
 RESTParameters::~RESTParameters(){