diff --git a/src/ESPAsyncWebServer.h b/src/ESPAsyncWebServer.h
index f729f7e..a12165b 100644
--- a/src/ESPAsyncWebServer.h
+++ b/src/ESPAsyncWebServer.h
@@ -293,11 +293,11 @@ class AsyncWebServerRequest {
     void redirect(const String& url) { return redirect(url.c_str()); };
 
     void send(AsyncWebServerResponse* response);
-    void send(int code, const String& contentType = String(), const String& content = String());
+    void send(int code, const String& contentType = emptyString, const String& content = emptyString);
     void send(int code, const String& contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr);
     void send(int code, const String& contentType, PGM_P content, AwsTemplateProcessor callback = nullptr);
-    void send(FS& fs, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
-    void send(File content, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
+    void send(FS& fs, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
+    void send(File content, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
     void send(Stream& stream, const String& contentType, size_t len, AwsTemplateProcessor callback = nullptr);
     void send(const String& contentType, size_t len, AwsResponseFiller callback, AwsTemplateProcessor templateCallback = nullptr);
     void sendChunked(const String& contentType, AwsResponseFiller callback, AwsTemplateProcessor templateCallback = nullptr);
@@ -311,11 +311,11 @@ class AsyncWebServerRequest {
       send(code, contentType, content, callback);
     }
 
-    AsyncWebServerResponse* beginResponse(int code, const String& contentType = String(), const String& content = String());
+    AsyncWebServerResponse* beginResponse(int code, const String& contentType = emptyString, const String& content = emptyString);
     AsyncWebServerResponse* beginResponse(int code, const String& contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(int code, const String& contentType, PGM_P content, AwsTemplateProcessor callback = nullptr);
-    AsyncWebServerResponse* beginResponse(FS& fs, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
-    AsyncWebServerResponse* beginResponse(File content, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncWebServerResponse* beginResponse(FS& fs, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncWebServerResponse* beginResponse(File content, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(Stream& stream, const String& contentType, size_t len, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(const String& contentType, size_t len, AwsResponseFiller callback, AwsTemplateProcessor templateCallback = nullptr);
     AsyncWebServerResponse* beginChunkedResponse(const String& contentType, AwsResponseFiller callback, AwsTemplateProcessor templateCallback = nullptr);
diff --git a/src/WebRequest.cpp b/src/WebRequest.cpp
index f0d6bdf..01549f0 100644
--- a/src/WebRequest.cpp
+++ b/src/WebRequest.cpp
@@ -274,7 +274,7 @@ bool AsyncWebServerRequest::_parseReqHead() {
   if (!_temp.startsWith(T_HTTP_1_0))
     _version = 1;
 
-  _temp = String();
+  _temp = emptyString;
   return true;
 }
 
@@ -327,7 +327,7 @@ bool AsyncWebServerRequest::_parseReqHeader() {
   _temp.clear();
 #else
   // Ancient PRI core does not have String::clear() method 8-()
-  _temp = String();
+  _temp = emptyString;
 #endif
   return true;
 }
@@ -348,7 +348,7 @@ void AsyncWebServerRequest::_parsePlainPostChar(uint8_t data) {
   _temp.clear();
 #else
   // Ancient PRI core does not have String::clear() method 8-()
-  _temp = String();
+  _temp = emptyString;
 #endif
   }
 }
@@ -390,10 +390,10 @@ void AsyncWebServerRequest::_parseMultipartPostByte(uint8_t data, bool last) {
 
   if (!_parsedLength) {
     _multiParseState = EXPECT_BOUNDARY;
-    _temp = String();
-    _itemName = String();
-    _itemFilename = String();
-    _itemType = String();
+    _temp = emptyString;
+    _itemName = emptyString;
+    _itemFilename = emptyString;
+    _itemType = emptyString;
   }
 
   if (_multiParseState == WAIT_FOR_RETURN1) {
@@ -450,13 +450,13 @@ void AsyncWebServerRequest::_parseMultipartPostByte(uint8_t data, bool last) {
             _itemIsFile = true;
           }
         }
-        _temp = String();
+        _temp = emptyString;
       } else {
         _multiParseState = WAIT_FOR_RETURN1;
         // value starts from here
         _itemSize = 0;
         _itemStartIndex = _parsedLength;
-        _itemValue = String();
+        _itemValue = emptyString;
         if (_itemIsFile) {
           if (_itemBuffer)
             free(_itemBuffer);
diff --git a/src/WebResponseImpl.h b/src/WebResponseImpl.h
index 26ec223..ed7a55e 100644
--- a/src/WebResponseImpl.h
+++ b/src/WebResponseImpl.h
@@ -36,7 +36,7 @@ class AsyncBasicResponse : public AsyncWebServerResponse {
     String _content;
 
   public:
-    AsyncBasicResponse(int code, const String& contentType = String(), const String& content = String());
+    AsyncBasicResponse(int code, const String& contentType = emptyString, const String& content = emptyString);
     void _respond(AsyncWebServerRequest* request);
     size_t _ack(AsyncWebServerRequest* request, size_t len, uint32_t time);
     bool _sourceValid() const { return true; }
@@ -79,8 +79,8 @@ class AsyncFileResponse : public AsyncAbstractResponse {
     void _setContentType(const String& path);
 
   public:
-    AsyncFileResponse(FS& fs, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
-    AsyncFileResponse(File content, const String& path, const String& contentType = String(), bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncFileResponse(FS& fs, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncFileResponse(File content, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr);
     ~AsyncFileResponse();
     bool _sourceValid() const { return !!(_content); }
     virtual size_t _fillBuffer(uint8_t* buf, size_t maxLen) override;
diff --git a/src/WebResponses.cpp b/src/WebResponses.cpp
index 86aa947..ce05d6e 100644
--- a/src/WebResponses.cpp
+++ b/src/WebResponses.cpp
@@ -353,7 +353,7 @@ size_t AsyncBasicResponse::_ack(AsyncWebServerRequest* request, size_t len, uint
     // we can fit in this packet
     if (space > available) {
       _writtenLength += request->client()->write(_content.c_str(), available);
-      _content = String();
+      _content = emptyString;
       _state = RESPONSE_WAIT_ACK;
       return available;
     }
@@ -465,7 +465,7 @@ size_t AsyncAbstractResponse::_ack(AsyncWebServerRequest* request, size_t len, u
     }
 
     if (headLen) {
-      _head = String();
+      _head = emptyString;
     }
 
     if (outLen) {