diff --git a/README.md b/README.md
index 254adcd..d200cda 100644
--- a/README.md
+++ b/README.md
@@ -124,8 +124,8 @@ espConnect.setIPConfig(ipConfig);
     switch (state) {
       case Mycila::ESPConnect::State::PORTAL_COMPLETE:
         bool apMode = espConnect.hasConfiguredAPMode();
-        String wifiSSID = espConnect.getConfiguredWiFiSSID();
-        String wifiPassword = espConnect.getConfiguredWiFiPassword();
+        std::string wifiSSID = espConnect.getConfiguredWiFiSSID();
+        std::string wifiPassword = espConnect.getConfiguredWiFiPassword();
         if (apMode) {
           Serial.println("====> Captive Portal: Access Point configured");
         } else {
diff --git a/docs/index.md b/docs/index.md
index 254adcd..d200cda 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -124,8 +124,8 @@ espConnect.setIPConfig(ipConfig);
     switch (state) {
       case Mycila::ESPConnect::State::PORTAL_COMPLETE:
         bool apMode = espConnect.hasConfiguredAPMode();
-        String wifiSSID = espConnect.getConfiguredWiFiSSID();
-        String wifiPassword = espConnect.getConfiguredWiFiPassword();
+        std::string wifiSSID = espConnect.getConfiguredWiFiSSID();
+        std::string wifiPassword = espConnect.getConfiguredWiFiPassword();
         if (apMode) {
           Serial.println("====> Captive Portal: Access Point configured");
         } else {
diff --git a/examples/AdvancedCaptivePortal/AdvancedCaptivePortal.ino b/examples/AdvancedCaptivePortal/AdvancedCaptivePortal.ino
index e98ba65..84bcd21 100644
--- a/examples/AdvancedCaptivePortal/AdvancedCaptivePortal.ino
+++ b/examples/AdvancedCaptivePortal/AdvancedCaptivePortal.ino
@@ -77,8 +77,8 @@ void setup() {
   Preferences preferences;
   preferences.begin("app", true);
   Mycila::ESPConnect::Config config = {
-    .wifiSSID = preferences.isKey("ssid") ? preferences.getString("ssid", emptyString) : emptyString,
-    .wifiPassword = preferences.isKey("password") ? preferences.getString("password", emptyString) : emptyString,
+    .wifiSSID = (preferences.isKey("ssid") ? preferences.getString("ssid", emptyString) : emptyString).c_str(),
+    .wifiPassword = (preferences.isKey("password") ? preferences.getString("password", emptyString) : emptyString).c_str(),
     .apMode = preferences.isKey("ap") ? preferences.getBool("ap", false) : false};
   preferences.end();
 
diff --git a/examples/NonBlockingCaptivePortal/NonBlockingCaptivePortal.ino b/examples/NonBlockingCaptivePortal/NonBlockingCaptivePortal.ino
index ab936d2..8ae7137 100644
--- a/examples/NonBlockingCaptivePortal/NonBlockingCaptivePortal.ino
+++ b/examples/NonBlockingCaptivePortal/NonBlockingCaptivePortal.ino
@@ -3,7 +3,7 @@
 AsyncWebServer server(80);
 Mycila::ESPConnect espConnect(server);
 uint32_t lastLog = 0;
-String hostname = "arduino-1";
+const char* hostname = "arduino-1";
 
 void setup() {
   Serial.begin(115200);
@@ -63,7 +63,7 @@ void setup() {
 
   Serial.println("====> Trying to connect to saved WiFi or will start portal in the background...");
 
-  espConnect.begin(hostname.c_str(), "Captive Portal SSID");
+  espConnect.begin(hostname, "Captive Portal SSID");
 
   Serial.println("====> setup() completed...");
 }
diff --git a/examples/WiFiStaticIP/WiFiStaticIP.ino b/examples/WiFiStaticIP/WiFiStaticIP.ino
index eaefc84..ee288d8 100644
--- a/examples/WiFiStaticIP/WiFiStaticIP.ino
+++ b/examples/WiFiStaticIP/WiFiStaticIP.ino
@@ -4,7 +4,7 @@ AsyncWebServer server(80);
 Mycila::ESPConnect espConnect(server);
 uint32_t lastLog = 0;
 uint32_t lastChange = 0;
-String hostname = "arduino-1";
+const char* hostname = "arduino-1";
 
 void setup() {
   Serial.begin(115200);
@@ -50,7 +50,7 @@ void setup() {
 
   Serial.println("====> Trying to connect to saved WiFi or will start portal in the background...");
 
-  espConnect.begin(hostname.c_str(), "Captive Portal SSID");
+  espConnect.begin(hostname, "Captive Portal SSID");
 
   Serial.println("====> setup() completed...");
 }
diff --git a/platformio.ini b/platformio.ini
index 48834b1..ed1beb2 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -3,8 +3,8 @@
 default_envs = arduino-2, arduino-3, arduino-310, esp8266, esp32-poe-arduino-2, esp32-poe-arduino-3, esp32-poe-arduino-310, wt32-eth01-arduino-2, wt32-eth01-arduino-3, wt32-eth01-arduino-310, lilygo-eth-lite-s3-arduino-2, lilygo-eth-lite-s3-arduino-3, lilygo-eth-lite-s3-arduino-310
 lib_dir = .
 ; src_dir = examples/BlockingCaptivePortal
-; src_dir = examples/NonBlockingCaptivePortal
-src_dir = examples/AdvancedCaptivePortal
+src_dir = examples/NonBlockingCaptivePortal
+; src_dir = examples/AdvancedCaptivePortal
 ; src_dir = examples/TestWiFi8266
 ; src_dir = examples/WiFiStaticIP
 
diff --git a/src/MycilaESPConnect.cpp b/src/MycilaESPConnect.cpp
index a40acae..cc2d830 100644
--- a/src/MycilaESPConnect.cpp
+++ b/src/MycilaESPConnect.cpp
@@ -5,6 +5,7 @@
 #include "MycilaESPConnect.h"
 
 #include <cstdio>
+#include <string>
 
 #ifdef ESP8266
   #ifndef ESPCONNECT_NO_MDNS
@@ -135,38 +136,38 @@ Mycila::ESPConnect::Mode Mycila::ESPConnect::getMode() const {
   }
 }
 
-const String Mycila::ESPConnect::getMACAddress(Mycila::ESPConnect::Mode mode) const {
-  String mac;
+std::string Mycila::ESPConnect::getMACAddress(Mycila::ESPConnect::Mode mode) const {
+  std::string mac;
 
   switch (mode) {
     case Mycila::ESPConnect::Mode::AP:
-      mac = WiFi.softAPmacAddress();
+      mac = WiFi.softAPmacAddress().c_str();
       break;
     case Mycila::ESPConnect::Mode::STA:
-      mac = WiFi.macAddress();
+      mac = WiFi.macAddress().c_str();
       break;
 #ifdef ESPCONNECT_ETH_SUPPORT
     case Mycila::ESPConnect::Mode::ETH:
-      mac = ETH.linkUp() ? ETH.macAddress() : emptyString;
+      if (ETH.linkUp())
+        mac = ETH.macAddress().c_str();
       break;
 #endif
     default:
-      mac = emptyString;
       break;
   }
 
-  if (mac != emptyString && mac != "00:00:00:00:00:00")
+  if (!mac.empty() && mac != "00:00:00:00:00:00")
     return mac;
 
 #ifdef ESP8266
   switch (mode) {
     case Mycila::ESPConnect::Mode::AP:
-      return WiFi.softAPmacAddress();
+      return WiFi.softAPmacAddress().c_str();
     case Mycila::ESPConnect::Mode::STA:
-      return WiFi.macAddress();
+      return WiFi.macAddress().c_str();
     default:
       // ETH not supported with ESP8266
-      return emptyString;
+      return {};
   }
 #else
   // ESP_MAC_IEEE802154 is used to mean "no MAC address" in this context
@@ -189,11 +190,11 @@ const String Mycila::ESPConnect::getMACAddress(Mycila::ESPConnect::Mode mode) co
   }
 
   if (type == esp_mac_type_t::ESP_MAC_IEEE802154)
-    return emptyString;
+    return "";
 
   uint8_t bytes[6] = {0, 0, 0, 0, 0, 0};
   if (esp_read_mac(bytes, type) != ESP_OK)
-    return emptyString;
+    return "";
 
   char buffer[18] = {0};
   snprintf(buffer, sizeof(buffer), "%02X:%02X:%02X:%02X:%02X:%02X", bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5]);
@@ -201,7 +202,7 @@ const String Mycila::ESPConnect::getMACAddress(Mycila::ESPConnect::Mode mode) co
 #endif
 }
 
-const IPAddress Mycila::ESPConnect::getIPAddress(Mycila::ESPConnect::Mode mode) const {
+IPAddress Mycila::ESPConnect::getIPAddress(Mycila::ESPConnect::Mode mode) const {
   const wifi_mode_t wifiMode = WiFi.getMode();
   switch (mode) {
     case Mycila::ESPConnect::Mode::AP:
@@ -217,7 +218,7 @@ const IPAddress Mycila::ESPConnect::getIPAddress(Mycila::ESPConnect::Mode mode)
   }
 }
 
-const String& Mycila::ESPConnect::getWiFiSSID() const {
+std::string Mycila::ESPConnect::getWiFiSSID() const {
   switch (WiFi.getMode()) {
     case WIFI_MODE_AP:
     case WIFI_MODE_APSTA:
@@ -225,19 +226,19 @@ const String& Mycila::ESPConnect::getWiFiSSID() const {
     case WIFI_MODE_STA:
       return _config.wifiSSID;
     default:
-      return emptyString;
+      return {};
   }
 }
 
-const String Mycila::ESPConnect::getWiFiBSSID() const {
+std::string Mycila::ESPConnect::getWiFiBSSID() const {
   switch (WiFi.getMode()) {
     case WIFI_MODE_AP:
     case WIFI_MODE_APSTA:
-      return WiFi.softAPmacAddress();
+      return WiFi.softAPmacAddress().c_str();
     case WIFI_MODE_STA:
-      return WiFi.BSSIDstr();
+      return WiFi.BSSIDstr().c_str();
     default:
-      return emptyString;
+      return {};
   }
 }
 
@@ -263,8 +264,12 @@ void Mycila::ESPConnect::begin(const char* hostname, const char* apSSID, const c
   LOGD(TAG, "Loading config...");
   Preferences preferences;
   preferences.begin("espconnect", true);
-  String ssid = preferences.isKey("ssid") ? preferences.getString("ssid", emptyString) : emptyString;
-  String password = preferences.isKey("password") ? preferences.getString("password", emptyString) : emptyString;
+  std::string ssid;
+  std::string password;
+  if (preferences.isKey("ssid"))
+    ssid = preferences.getString("ssid").c_str();
+  if (preferences.isKey("password"))
+    password = preferences.getString("password").c_str();
   bool ap = preferences.isKey("ap") ? preferences.getBool("ap", false) : false;
   preferences.end();
   LOGD(TAG, " - AP: %d", ap);
@@ -338,7 +343,7 @@ void Mycila::ESPConnect::loop() {
   // start captive portal when network enabled but not in ap mode and no wifi info and no ethernet
   // portal wil be interrupted when network connected
 #ifndef ESPCONNECT_ETH_SUPPORT
-  if (_state == Mycila::ESPConnect::State::NETWORK_ENABLED && _config.wifiSSID.isEmpty()) {
+  if (_state == Mycila::ESPConnect::State::NETWORK_ENABLED && _config.wifiSSID.empty()) {
     _startAP();
   }
 #endif
@@ -348,7 +353,7 @@ void Mycila::ESPConnect::loop() {
 #ifdef ESPCONNECT_ETH_SUPPORT
     _startEthernet();
 #endif
-    if (!_config.wifiSSID.isEmpty())
+    if (!_config.wifiSSID.empty())
       _startSTA();
   }
 
@@ -368,7 +373,7 @@ void Mycila::ESPConnect::loop() {
 
   // timeout portal if we failed to connect to WiFi (we got a SSID) and portal duration is passed
   // in order to restart and try again to connect to the configured WiFi
-  if (_state == Mycila::ESPConnect::State::PORTAL_STARTED && !_config.wifiSSID.isEmpty() && _durationPassed(_portalTimeout)) {
+  if (_state == Mycila::ESPConnect::State::PORTAL_STARTED && !_config.wifiSSID.empty() && _durationPassed(_portalTimeout)) {
     _setState(Mycila::ESPConnect::State::PORTAL_TIMEOUT);
   }
 
@@ -522,7 +527,7 @@ void Mycila::ESPConnect::_startSTA() {
 #endif
 
   LOGD(TAG, "Connecting to SSID: %s...", _config.wifiSSID.c_str());
-  WiFi.begin(_config.wifiSSID, _config.wifiPassword);
+  WiFi.begin(_config.wifiSSID.c_str(), _config.wifiPassword.c_str());
 
   _lastTime = millis();
 
@@ -548,11 +553,11 @@ void Mycila::ESPConnect::_startAP() {
 
   WiFi.mode(_config.apMode ? WIFI_AP : WIFI_AP_STA);
 
-  if (_apPassword.isEmpty() || _apPassword.length() < 8) {
+  if (_apPassword.empty() || _apPassword.length() < 8) {
     // Disabling invalid Access Point password which must be at least 8 characters long when set
-    WiFi.softAP(_apSSID, emptyString);
+    WiFi.softAP(_apSSID.c_str(), "");
   } else
-    WiFi.softAP(_apSSID, _apPassword);
+    WiFi.softAP(_apSSID.c_str(), _apPassword.c_str());
 
   if (_dnsServer == nullptr) {
     _dnsServer = new DNSServer();
@@ -628,16 +633,20 @@ void Mycila::ESPConnect::_enableCaptivePortal() {
 
   if (_connectHandler == nullptr) {
     _connectHandler = &_httpd->on("/espconnect/connect", HTTP_POST, [&](AsyncWebServerRequest* request) {
-      _config.apMode = (request->hasParam("ap_mode", true) ? request->getParam("ap_mode", true)->value() : emptyString) == "true";
+      _config.apMode = request->hasParam("ap_mode", true) && request->getParam("ap_mode", true)->value() == "true";
       if (_config.apMode) {
         request->send(200, "application/json", "{\"message\":\"Configuration Saved.\"}");
         _setState(Mycila::ESPConnect::State::PORTAL_COMPLETE);
       } else {
-        String ssid = request->hasParam("ssid", true) ? request->getParam("ssid", true)->value() : emptyString;
-        String password = request->hasParam("password", true) ? request->getParam("password", true)->value() : emptyString;
-        if (ssid.isEmpty())
+        std::string ssid;
+        std::string password;
+        if (request->hasParam("ssid", true))
+          ssid = request->getParam("ssid", true)->value().c_str();
+        if (request->hasParam("password", true))
+          password = request->getParam("password", true)->value().c_str();
+        if (ssid.empty())
           return request->send(400, "application/json", "{\"message\":\"Invalid SSID\"}");
-        if (ssid.length() > 32 || password.length() > 64 || (!password.isEmpty() && password.length() < 8))
+        if (ssid.length() > 32 || password.length() > 64 || (!password.empty() && password.length() < 8))
           return request->send(400, "application/json", "{\"message\":\"Credentials exceed character limit of 32 & 64 respectively, or password lower than 8 characters.\"}");
         _config.wifiSSID = ssid;
         _config.wifiPassword = password;
diff --git a/src/MycilaESPConnect.h b/src/MycilaESPConnect.h
index b7f4cb3..347ce68 100644
--- a/src/MycilaESPConnect.h
+++ b/src/MycilaESPConnect.h
@@ -9,6 +9,8 @@
 #include <DNSServer.h>
 #include <ESPAsyncWebServer.h>
 
+#include <string>
+
 #define ESPCONNECT_VERSION          "6.1.1"
 #define ESPCONNECT_VERSION_MAJOR    6
 #define ESPCONNECT_VERSION_MINOR    1
@@ -83,9 +85,9 @@ namespace Mycila {
 
       typedef struct {
           // SSID name to connect to, loaded from config or set from begin(), or from the captive portal
-          String wifiSSID;
+          std::string wifiSSID;
           // Password for the WiFi to connect to, loaded from config or set from begin(), or from the captive portal
-          String wifiPassword;
+          std::string wifiPassword;
           // whether we need to set the ESP to stay in AP mode or not, loaded from config, begin(), or from captive portal
           bool apMode;
       } Config;
@@ -133,36 +135,36 @@ namespace Mycila {
 
       bool isConnected() const { return getIPAddress()[0] != 0; }
 
-      const String getMACAddress() const { return getMACAddress(getMode()); }
-      const String getMACAddress(Mode mode) const;
+      std::string getMACAddress() const { return getMACAddress(getMode()); }
+      std::string getMACAddress(Mode mode) const;
 
       // Returns the IP address of the current Ethernet, WiFi, or IP address of the AP or captive portal, or empty if not available
-      const IPAddress getIPAddress() const { return getIPAddress(getMode()); }
-      const IPAddress getIPAddress(Mode mode) const;
+      IPAddress getIPAddress() const { return getIPAddress(getMode()); }
+      IPAddress getIPAddress(Mode mode) const;
 
-      // Returns the SSID of the current WiFi, or SSID of the AP or captive portal, or empty if not available
-      const String& getWiFiSSID() const;
+      // Returns the configured WiFi SSID or the configured SSID of the AP or captive portal, or empty if not available, depending on the current mode
+      std::string getWiFiSSID() const;
       // Returns the BSSID of the current WiFi, or BSSID of the AP or captive portal, or empty if not available
-      const String getWiFiBSSID() const;
+      std::string getWiFiBSSID() const;
       // Returns the RSSI of the current WiFi, or -1 if not available
       int8_t getWiFiRSSI() const;
       // Returns the signal quality (percentage from 0 to 100) of the current WiFi, or -1 if not available
       int8_t getWiFiSignalQuality() const;
 
       // the hostname passed from begin()
-      const String& getHostname() const { return _hostname; }
+      const std::string& getHostname() const { return _hostname; }
 
       // SSID name used for the captive portal or in AP mode
-      const String& getAccessPointSSID() const { return _apSSID; }
+      const std::string& getAccessPointSSID() const { return _apSSID; }
       // Password used for the captive portal or in AP mode
-      const String& getAccessPointPassword() const { return _apPassword; }
+      const std::string& getAccessPointPassword() const { return _apPassword; }
 
       // Returns the current configuration loaded or passed from begin() or from captive portal
       const Config& getConfig() const { return _config; }
       // SSID name to connect to, loaded from config or set from begin(), or from the captive portal
-      const String& getConfiguredWiFiSSID() const { return _config.wifiSSID; }
+      const std::string& getConfiguredWiFiSSID() const { return _config.wifiSSID; }
       // Password for the WiFi to connect to, loaded from config or set from begin(), or from the captive portal
-      const String& getConfiguredWiFiPassword() const { return _config.wifiPassword; }
+      const std::string& getConfiguredWiFiPassword() const { return _config.wifiPassword; }
       // whether we need to set the ESP to stay in AP mode or not, loaded from config, begin(), or from captive portal
       bool hasConfiguredAPMode() const { return _config.apMode; }
 
@@ -203,9 +205,9 @@ namespace Mycila {
       StateCallback _callback = nullptr;
       DNSServer* _dnsServer = nullptr;
       int64_t _lastTime = -1;
-      String _hostname = emptyString;
-      String _apSSID = emptyString;
-      String _apPassword = emptyString;
+      std::string _hostname;
+      std::string _apSSID;
+      std::string _apPassword;
       uint32_t _connectTimeout = ESPCONNECT_CONNECTION_TIMEOUT;
       uint32_t _portalTimeout = ESPCONNECT_PORTAL_TIMEOUT;
       Config _config;