diff --git a/include/Network.h b/include/Network.h
index 736b17e..147ab60 100644
--- a/include/Network.h
+++ b/include/Network.h
@@ -46,6 +46,7 @@ class WiFiManager {
 
     void handleClient();
     void startCaptivePortal();
+    void handleApiWifi();
     void handleRoot();
     void handleSave();
     void handleNotFound();
@@ -70,6 +71,7 @@ class WiFiManager {
     private:
       bool isAccessPoint = false;
       bool captivePortalActive = false;
+      bool serverActive = false;
       WebServer server{80};
       DNSServer dnsServer;
       int expectedCaptchaAnswer = 0;
diff --git a/src/Network.cpp b/src/Network.cpp
index 70b475d..d9b1fd6 100644
--- a/src/Network.cpp
+++ b/src/Network.cpp
@@ -107,6 +107,12 @@ void WiFiManager::connectToWiFi() {
     ESP_LOGI(WIFI, "%s", gatewayInfo.c_str());
     String dnsInfo = "DNS: " + WiFi.dnsIP().toString();
     ESP_LOGI(WIFI, "%s", dnsInfo.c_str());
+    
+    // Start background API server
+    server.on("/api/wifi", HTTP_POST, std::bind(&WiFiManager::handleApiWifi, this));
+    server.begin();
+    serverActive = true;
+    ESP_LOGI(WIFI, "REST API Server started on port 80");
    } else {
     String infoWiFi = "WIFI CONNECTION ERROR: ALL FAILED";
     ESP_LOGI(WIFI, "%s", infoWiFi.c_str());
@@ -300,10 +306,33 @@ void WiFiManager::startCaptivePortal() {
 void WiFiManager::handleClient() {
   if (captivePortalActive) {
     dnsServer.processNextRequest();
+  }
+  if (captivePortalActive || serverActive) {
     server.handleClient();
   }
 }
 
+void WiFiManager::handleApiWifi() {
+  if (!server.hasArg("ssid") || !server.hasArg("password")) {
+    server.send(400, "text/plain", "Error: Missing 'ssid' or 'password' parameter.");
+    return;
+  }
+  
+  String newSSID = server.arg("ssid");
+  String newPass = server.arg("password");
+  
+  File f = SD.open("/wifi.txt", FILE_APPEND);
+  if (f) {
+    f.println(newSSID + ";" + newPass);
+    f.close();
+    server.send(200, "text/plain", "Success: WiFi credentials saved to SD card.");
+    ESP_LOGI(WIFI, "API received new WiFi config: %s", newSSID.c_str());
+  } else {
+    server.send(500, "text/plain", "Error: Cannot open wifi.txt on SD card.");
+    ESP_LOGE(WIFI, "API Error: Cannot open wifi.txt");
+  }
+}
+
 void WiFiManager::handleRoot() {
   int bases[] = {2, 2, 2, 2, 3, 3, 10, 10};
   int vals[] = {4, 8, 16, 32, 9, 27, 100, 1000};