#include <SoftwareSerial.h>
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <ArduinoJson.h>

// WiFi credentials
const char* ssid = "YourWiFiNetwork";
const char* password = "YourPassword";

// Payment configuration
const String receiverAddress = "0xa78eD39F695615315458Bb066ac9a5F28Dfd65FE";
const String network = "base-sepolia";
const float paymentAmount = 1.0; // USDC amount

// Create web server on port 80
ESP8266WebServer server(80);

// Payment verification endpoint
void handlePaymentRequest() {
    if (server.method() == HTTP_POST) {
        String payload = server.arg("plain");
        
        // Parse JSON payload from sender
        DynamicJsonDocument doc(1024);
        deserializeJson(doc, payload);
        
        String senderAddress = doc["from"];
        String txHash = doc["txHash"];
        float amount = doc["amount"];
        
        // Verify payment via PayNet facilitator API
        String apiUrl = "https://facilitator.neptune.cloud/verify";
        HTTPClient http;
        http.begin(apiUrl);
        http.addHeader("Content-Type", "application/json");
        
        String verifyPayload = "{"txHash":"" + txHash + 
                              "","network":"" + network + ""}";
        
        int httpCode = http.POST(verifyPayload);
        
        if (httpCode == 200) {
            String response = http.getString();
            DynamicJsonDocument verifyDoc(512);
            deserializeJson(verifyDoc, response);
            
            if (verifyDoc["verified"] == true && 
                verifyDoc["to"] == receiverAddress &&
                verifyDoc["amount"] >= paymentAmount) {
                
                // Payment verified - transfer complete
                server.send(200, "application/json", 
                    "{"status":"success","message":"Payment received"}");
                
                Serial.println("Payment verified: $" + String(amount) + 
                              " from " + senderAddress);
                
                // Activate your device (e.g., unlock door, dispense item)
                digitalWrite(LED_BUILTIN, HIGH);
                delay(1000);
                digitalWrite(LED_BUILTIN, LOW);
            }
        }
        http.end();
    }
}

void setup() {
    Serial.begin(115200);
    pinMode(LED_BUILTIN, OUTPUT);
    
    // Connect to WiFi
    WiFi.begin(ssid, password);
    Serial.print("Connecting to WiFi");
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println();
    Serial.print("WiFi connected! IP: ");
    Serial.println(WiFi.localIP());
    
    // Setup payment endpoint
    server.on("/payment", handlePaymentRequest);
    server.begin();
    Serial.println("Payment server started on /payment");
}

void loop() {
    server.handleClient();
    delay(10);
}

Connection Times

WiFi Association & DHCP: 1-3 seconds
HTTP Request/Response Setup: <200 ms
Endpoint Availability Check: <