diff --git a/JsonListener.h b/JsonListener.h
index 7cfb197..6e280e7 100644
--- a/JsonListener.h
+++ b/JsonListener.h
@@ -40,9 +40,9 @@ class JsonListener {
   
     virtual void startDocument() = 0;
 
-    virtual void key(String key) = 0;
+    virtual void key(const char *key) = 0;
 
-    virtual void value(String value) = 0;
+    virtual void value(const char *value) = 0;
 
     virtual void endArray() = 0;
 
diff --git a/JsonStreamingParser.cpp b/JsonStreamingParser.cpp
index 3ae687f..72c50c3 100644
--- a/JsonStreamingParser.cpp
+++ b/JsonStreamingParser.cpp
@@ -210,11 +210,11 @@ void JsonStreamingParser::endString() {
     stackPos--;
     if (popped == STACK_KEY) {
       buffer[bufferPos] = '\0';
-      myListener->key(String(buffer));
+      myListener->key(buffer);
       state = STATE_END_KEY;
     } else if (popped == STACK_STRING) {
       buffer[bufferPos] = '\0';
-      myListener->value(String(buffer));
+      myListener->value(buffer);
       state = STATE_AFTER_VALUE;
     } else {
       // throw new ParsingError($this->_line_number, $this->_char_number,
@@ -404,7 +404,7 @@ void JsonStreamingParser::endUnicodeSurrogateInterstitial() {
 
 void JsonStreamingParser::endNumber() {
     buffer[bufferPos] = '\0';
-    String value = String(buffer);
+    // String value = String(buffer);
     //float result = 0.0;
     //if (doesCharArrayContain(buffer, bufferPos, '.')) {
     //  result = value.toFloat();
@@ -412,7 +412,7 @@ void JsonStreamingParser::endNumber() {
       // needed special treatment in php, maybe not in Java and c
     //  result = value.toFloat();
     //}
-    myListener->value(value.c_str());
+    myListener->value(buffer);
     bufferPos = 0;
     state = STATE_AFTER_VALUE;
   }
@@ -433,8 +433,8 @@ void JsonStreamingParser::endDocument() {
 
 void JsonStreamingParser::endTrue() {
     buffer[bufferPos] = '\0';
-    String value = String(buffer);
-    if (value == "true") {
+    // String value = String(buffer);
+    if (strncmp(buffer, "true", 4) == 0) {
       myListener->value("true");
     } else {
       // throw new ParsingError($this->_line_number, $this->_char_number,
@@ -446,8 +446,8 @@ void JsonStreamingParser::endTrue() {
 
 void JsonStreamingParser::endFalse() {
     buffer[bufferPos] = '\0';
-    String value = String(buffer);
-    if (value == "false") {
+    // String value = String(buffer);
+    if (strncmp(buffer, "false",5) == 0 ) {
       myListener->value("false");
     } else {
       // throw new ParsingError($this->_line_number, $this->_char_number,
@@ -459,8 +459,8 @@ void JsonStreamingParser::endFalse() {
 
 void JsonStreamingParser::endNull() {
     buffer[bufferPos] = '\0';
-    String value = String(buffer);
-    if (value == "null") {
+    // String value = String(buffer);
+    if (strncmp(buffer, "null", 4) == 0) {
       myListener->value("null");
     } else {
       // throw new ParsingError($this->_line_number, $this->_char_number,
diff --git a/examples/JsonStreamingParser/ExampleParser.cpp b/examples/JsonStreamingParser/ExampleParser.cpp
index 0656fdb..88ea096 100644
--- a/examples/JsonStreamingParser/ExampleParser.cpp
+++ b/examples/JsonStreamingParser/ExampleParser.cpp
@@ -10,12 +10,14 @@ void ExampleListener::startDocument() {
   Serial.println("start document");
 }
 
-void ExampleListener::key(String key) {
-  Serial.println("key: " + key);
+void ExampleListener::key(const char *key) {
+  Serial.print("key: ");
+  Serial.println(key);
 }
 
-void ExampleListener::value(String value) {
-  Serial.println("value: " + value);
+void ExampleListener::value(const char *value) {
+  Serial.print("value: ");
+  Serial.print(value);
 }
 
 void ExampleListener::endArray() {
diff --git a/examples/JsonStreamingParser/ExampleParser.h b/examples/JsonStreamingParser/ExampleParser.h
index c5f6f79..a986491 100644
--- a/examples/JsonStreamingParser/ExampleParser.h
+++ b/examples/JsonStreamingParser/ExampleParser.h
@@ -9,9 +9,9 @@ class ExampleListener: public JsonListener {
   
     virtual void startDocument();
 
-    virtual void key(String key);
+    virtual void key(const char *key);
 
-    virtual void value(String value);
+    virtual void value(const char *value);
 
     virtual void endArray();
 
diff --git a/examples/JsonStreamingParser/JsonStreamingParser.ino b/examples/JsonStreamingParser/JsonStreamingParser.ino
index fd6222c..fa7585f 100644
--- a/examples/JsonStreamingParser/JsonStreamingParser.ino
+++ b/examples/JsonStreamingParser/JsonStreamingParser.ino
@@ -7,14 +7,18 @@ ExampleListener listener;
 
 void setup() {
   Serial.begin(115200);
+#ifdef ARDUINO_ARCH_ESP8266
   Serial.println(String(ESP.getFreeHeap()));
+#endif
   parser.setListener(&listener);
   // put your setup code here, to run once:
   char json[] = "{\"a\":3, \"b\":{\"c\":\"d\"}}";
   for (int i = 0; i < sizeof(json); i++) {
     parser.parse(json[i]); 
   }
+#ifdef ARDUINO_ARCH_ESP8266
   Serial.println(String(ESP.getFreeHeap()));
+#endif
 }
 
 void loop() {