diff --git a/arangod/Agency/Constituent.cpp b/arangod/Agency/Constituent.cpp
index bf9d5a377b..c6e584422e 100644
--- a/arangod/Agency/Constituent.cpp
+++ b/arangod/Agency/Constituent.cpp
@@ -113,7 +113,7 @@ void Constituent::termNoLock(term_t t, std::string const& votedFor) {
 
   if (tmp != t || tmpVotedFor != votedFor) {
     LOG_TOPIC(INFO, Logger::AGENCY) << _id << ": changing term or votedFor, "
-      << "current role:" << roleStr[_role] << " term " << t << " votedFor: "
+      << "current role: " << roleStr[_role] << " term " << t << " votedFor: "
       << votedFor;
 
     Builder body;
diff --git a/arangod/Cluster/ClusterComm.h b/arangod/Cluster/ClusterComm.h
index a852eec081..382b7c00fa 100644
--- a/arangod/Cluster/ClusterComm.h
+++ b/arangod/Cluster/ClusterComm.h
@@ -270,13 +270,12 @@ struct ClusterCommResult {
         dynamic_cast<HttpResponse*>(response.get())->body().c_str(),
         dynamic_cast<HttpResponse*>(response.get())->body().length(), std::unordered_map<std::string,std::string>());
 
-    auto headers = response->headers();
+    auto const& headers = response->headers();
     auto errorCodes = headers.find(StaticStrings::ErrorCodes);
     if (errorCodes != headers.end()) {
       request->setHeader(StaticStrings::ErrorCodes, errorCodes->second);
     }
-    request->setHeader("x-arango-response-code",
-                       GeneralResponse::responseString(answer_code));
+    request->setHeader(StaticStrings::ResponseCode, GeneralResponse::responseString(answer_code));
     answer.reset(request);
     TRI_ASSERT(response != nullptr);
     result = std::make_shared<httpclient::SimpleHttpCommunicatorResult>(
diff --git a/arangod/Cluster/ClusterMethods.cpp b/arangod/Cluster/ClusterMethods.cpp
index 8313ca6380..e0578d6b4f 100644
--- a/arangod/Cluster/ClusterMethods.cpp
+++ b/arangod/Cluster/ClusterMethods.cpp
@@ -285,7 +285,7 @@ static void mergeResultsAllShards(
 static void extractErrorCodes(ClusterCommResult const& res,
                               std::unordered_map<int, size_t>& errorCounter,
                               bool includeNotFound) {
-  auto resultHeaders = res.answer->headers();
+  auto const& resultHeaders = res.answer->headers();
   auto codes = resultHeaders.find(StaticStrings::ErrorCodes);
   if (codes != resultHeaders.end()) {
     auto parsedCodes = VPackParser::fromJson(codes->second);
diff --git a/arangod/Cluster/RestClusterHandler.cpp b/arangod/Cluster/RestClusterHandler.cpp
index 9238e8c825..f9a42c8c97 100644
--- a/arangod/Cluster/RestClusterHandler.cpp
+++ b/arangod/Cluster/RestClusterHandler.cpp
@@ -105,7 +105,7 @@ void RestClusterHandler::handleCommandEndpoints() {
       // endpoint value, and can tell the following two cases apart:
       // - endpoint value is not empty: there is a leader, and it is known
       // - endpoint value is empty: leadership challenge is ongoing, current leader is unknown
-      _response->setHeader(StaticStrings::LeaderEndpoint, "");
+      _response->setHeaderNC(StaticStrings::LeaderEndpoint, "");
       return;
     }
       
diff --git a/arangod/GeneralServer/RestHandlerFactory.cpp b/arangod/GeneralServer/RestHandlerFactory.cpp
index 16ac8cbff4..34916a1c0e 100644
--- a/arangod/GeneralServer/RestHandlerFactory.cpp
+++ b/arangod/GeneralServer/RestHandlerFactory.cpp
@@ -69,7 +69,7 @@ class MaintenanceHandler : public RestBaseHandler {
         }
         generateError(Result(TRI_ERROR_CLUSTER_NOT_LEADER));
         // return the endpoint of the actual leader
-        _response->setHeader(StaticStrings::LeaderEndpoint, endpoint);
+        _response->setHeaderNC(StaticStrings::LeaderEndpoint, endpoint);
         break;
       }
 
@@ -78,7 +78,7 @@ class MaintenanceHandler : public RestBaseHandler {
         // intentionally do not set "Location" header, but use a custom header that 
         // clients can inspect. if they find an empty endpoint, it means that there
         // is an ongoing leadership challenge
-        _response->setHeader(StaticStrings::LeaderEndpoint, "");
+        _response->setHeaderNC(StaticStrings::LeaderEndpoint, "");
         break;
       }
 
diff --git a/arangod/RestHandler/RestCollectionHandler.cpp b/arangod/RestHandler/RestCollectionHandler.cpp
index 942a310480..6f05371833 100644
--- a/arangod/RestHandler/RestCollectionHandler.cpp
+++ b/arangod/RestHandler/RestCollectionHandler.cpp
@@ -203,7 +203,7 @@ void RestCollectionHandler::handleCommandGet() {
   }
   if (found.ok()) {
     generateOk(rest::ResponseCode::OK, builder);
-    _response->setHeader("location", _request->requestPath());
+    _response->setHeaderNC(StaticStrings::Location, _request->requestPath());
   } else {
     generateError(found);
   }
@@ -400,7 +400,7 @@ void RestCollectionHandler::handleCommandPut() {
     generateError(found);
   } else if (res.ok()) {
     generateOk(rest::ResponseCode::OK, builder);
-    _response->setHeader("location", _request->requestPath());
+    _response->setHeaderNC(StaticStrings::Location, _request->requestPath());
   } else {
     generateError(res);
   }
diff --git a/arangod/V8Server/v8-actions.cpp b/arangod/V8Server/v8-actions.cpp
index 0717255ad1..ae1b2863d6 100644
--- a/arangod/V8Server/v8-actions.cpp
+++ b/arangod/V8Server/v8-actions.cpp
@@ -415,7 +415,7 @@ static v8::Handle<v8::Object> RequestCppToV8(v8::Isolate* isolate,
 
   // copy header fields
   v8::Handle<v8::Object> headerFields = v8::Object::New(isolate);
-
+  // intentional copy, as we will modify the headers later
   auto headers = request->headers();
 
   TRI_GET_GLOBAL_STRING(HeadersKey);
@@ -526,7 +526,7 @@ static v8::Handle<v8::Object> RequestCppToV8(v8::Isolate* isolate,
   TRI_GET_GLOBAL_STRING(ParametersKey);
   req->ForceSet(ParametersKey, valuesObject);
 
-  // copy cookie -- only for http protocl
+  // copy cookie -- only for http protocol
   if (request->transportType() == Endpoint::TransportType::HTTP) {  // FIXME
     v8::Handle<v8::Object> cookiesObject = v8::Object::New(isolate);
 
@@ -591,8 +591,8 @@ static void ResponseV8ToCpp(v8::Isolate* isolate, TRI_v8_global_t const* v8g,
         break;
 
       case Endpoint::TransportType::VST:
-        response->setHeader(arangodb::StaticStrings::ContentTypeHeader,
-                            contentType);
+        response->setHeaderNC(arangodb::StaticStrings::ContentTypeHeader,
+                              contentType);
         break;
 
       default:
diff --git a/arangod/VocBase/Methods/Transactions.h b/arangod/VocBase/Methods/Transactions.h
index 06d0443efa..be722e7922 100644
--- a/arangod/VocBase/Methods/Transactions.h
+++ b/arangod/VocBase/Methods/Transactions.h
@@ -1,5 +1,5 @@
 #ifndef ARANGOD_VOCBASE_METHODS_TRANSACTIONS_HANDLER_H
-#define ARANGOD_VOCBASW_METHODS_TRANSACTIONS_HANDLER_H 1
+#define ARANGOD_VOCBASE_METHODS_TRANSACTIONS_HANDLER_H 1
 
 #include "Basics/ReadWriteLock.h"
 #include "Basics/Result.h"
diff --git a/lib/Basics/StaticStrings.cpp b/lib/Basics/StaticStrings.cpp
index 9880735a60..08de6c01ba 100644
--- a/lib/Basics/StaticStrings.cpp
+++ b/lib/Basics/StaticStrings.cpp
@@ -117,6 +117,7 @@ std::string const StaticStrings::Location("location");
 std::string const StaticStrings::MultiPartContentType("multipart/form-data");
 std::string const StaticStrings::NoSniff("nosniff");
 std::string const StaticStrings::Origin("origin");
+std::string const StaticStrings::ResponseCode("x-arango-response-code");
 std::string const StaticStrings::Queue("x-arango-queue");
 std::string const StaticStrings::Server("server");
 std::string const StaticStrings::StartThread("x-arango-start-thread");
diff --git a/lib/Basics/StaticStrings.h b/lib/Basics/StaticStrings.h
index 8c0f2741f4..083d8d43d6 100644
--- a/lib/Basics/StaticStrings.h
+++ b/lib/Basics/StaticStrings.h
@@ -112,6 +112,7 @@ class StaticStrings {
   static std::string const MultiPartContentType;
   static std::string const NoSniff;
   static std::string const Origin;
+  static std::string const ResponseCode;
   static std::string const Queue;
   static std::string const Server;
   static std::string const StartThread;
diff --git a/lib/Rest/GeneralResponse.cpp b/lib/Rest/GeneralResponse.cpp
index 9b77133be8..a957be0e48 100644
--- a/lib/Rest/GeneralResponse.cpp
+++ b/lib/Rest/GeneralResponse.cpp
@@ -433,7 +433,6 @@ rest::ResponseCode GeneralResponse::responseCode(int code) {
 
 GeneralResponse::GeneralResponse(ResponseCode responseCode)
     : _responseCode(responseCode),
-      _headers(),
       _contentType(ContentType::UNSET),
       _connectionType(ConnectionType::C_NONE),
       _options(velocypack::Options::Defaults),
diff --git a/lib/Rest/GeneralResponse.h b/lib/Rest/GeneralResponse.h
index 12692f37bc..84f89afb32 100644
--- a/lib/Rest/GeneralResponse.h
+++ b/lib/Rest/GeneralResponse.h
@@ -104,7 +104,7 @@ class GeneralResponse {
     _headers = std::move(headers);
   }
 
-  std::unordered_map<std::string, std::string> headers() const {
+  std::unordered_map<std::string, std::string> const& headers() const {
     return _headers;
   }
   
@@ -155,10 +155,10 @@ class GeneralResponse {
                   bool resolveExternals = true) = 0;
   
   virtual int reservePayload(std::size_t size) { return TRI_ERROR_NO_ERROR; }
-  bool generateBody() const { return _generateBody; };  // used for head
+  bool generateBody() const { return _generateBody; }  // used for head
   virtual bool setGenerateBody(bool) {
     return _generateBody;
-  };  // used for head
+  }  // used for head
       // resonses
   void setOptions(VPackOptions options) { _options = std::move(options); };
 
diff --git a/lib/Rest/HttpRequest.h b/lib/Rest/HttpRequest.h
index b17631e837..55c01d7004 100644
--- a/lib/Rest/HttpRequest.h
+++ b/lib/Rest/HttpRequest.h
@@ -34,7 +34,6 @@ class RestBatchHandler;
 namespace rest {
 class GeneralCommTask;
 class HttpCommTask;
-class HttpsCommTask;
 }
 
 namespace velocypack {
@@ -44,7 +43,6 @@ struct Options;
 
 class HttpRequest final : public GeneralRequest {
   friend class rest::HttpCommTask;
-  friend class rest::HttpsCommTask;
   friend class rest::GeneralCommTask;
   friend class RestBatchHandler;  // TODO must be removed
 
diff --git a/lib/Rest/HttpResponse.cpp b/lib/Rest/HttpResponse.cpp
index d7462f2dd1..08b018ca11 100644
--- a/lib/Rest/HttpResponse.cpp
+++ b/lib/Rest/HttpResponse.cpp
@@ -223,7 +223,7 @@ void HttpResponse::writeHeader(StringBuffer* output) {
 
   // add "Server" response header
   if (!seenServerHeader && !HIDE_PRODUCT_HEADER) {
-    output->appendText("Server: ArangoDB\r\n");
+    output->appendText(TRI_CHAR_LENGTH_PAIR("Server: ArangoDB\r\n"));
   }
 
   // add "Connection" response header
diff --git a/lib/Rest/VstRequest.cpp b/lib/Rest/VstRequest.cpp
index 3b0ccb228a..a70bc6c9e2 100644
--- a/lib/Rest/VstRequest.cpp
+++ b/lib/Rest/VstRequest.cpp
@@ -63,7 +63,6 @@ VstRequest::VstRequest(ConnectionInfo const& connectionInfo,
                        VstInputMessage&& message, uint64_t messageId, bool isFake)
     : GeneralRequest(connectionInfo),
       _message(std::move(message)),
-      _headers(nullptr),
       _messageId(messageId) {
   _protocol = "vst";
   _contentType = ContentType::VPACK;
diff --git a/lib/SimpleHttpClient/SimpleHttpCommunicatorResult.h b/lib/SimpleHttpClient/SimpleHttpCommunicatorResult.h
index 178e2d3934..3f335b7747 100644
--- a/lib/SimpleHttpClient/SimpleHttpCommunicatorResult.h
+++ b/lib/SimpleHttpClient/SimpleHttpCommunicatorResult.h
@@ -72,7 +72,7 @@ class SimpleHttpCommunicatorResult: public SimpleHttpResult {
       throw std::runtime_error(message);
     }
     virtual std::string getHeaderField(std::string const& header, bool& found) const override {
-      auto headers = _response->headers();
+      auto const& headers = _response->headers();
       auto it = headers.find(header);
       if (it == headers.end()) {
         return "";