From 45e99fe934482bed2a635cabddbf4ca24c8253cb Mon Sep 17 00:00:00 2001
From: Vedant1515 <vedant.pandya1515@gmail.com>
Date: Tue, 31 Mar 2026 23:48:25 +1100
Subject: [PATCH] BE06 - Implement centralized structured logging system

---
 controller/appointmentController.js         |  13 +-
 controller/authController.js                |  19 +-
 controller/chatbotController.js             |  17 +-
 controller/homeServiceController.js         |  17 +-
 controller/imageClassificationController.js |   5 +-
 controller/loginController.js               |  13 +-
 controller/medicalPredictionController.js   |   3 +-
 controller/notificationController.js        |  15 +-
 controller/uploadController.js              |   3 +-
 controller/userPreferencesController.js     |   5 +-
 middleware/requestLogger.js                 |  83 +++++++
 middleware/structuredErrorHandler.js        |  79 ++++++
 package-lock.json                           | 252 +++++++++++++++++++-
 package.json                                |   1 +
 server.js                                   |  28 +--
 utils/logger.js                             | 163 +++++++++++++
 16 files changed, 649 insertions(+), 67 deletions(-)
 create mode 100644 middleware/requestLogger.js
 create mode 100644 middleware/structuredErrorHandler.js
 create mode 100644 utils/logger.js

diff --git a/controller/appointmentController.js b/controller/appointmentController.js
index 854b96d9..9ea0dad8 100644
--- a/controller/appointmentController.js
+++ b/controller/appointmentController.js
@@ -1,5 +1,6 @@
 const {addAppointment, addAppointmentModelV2, updateAppointmentModel, deleteAppointmentById} = require('../model/appointmentModel.js');
 const {getAllAppointments, getAllAppointmentsV2 } = require('../model/getAppointments.js');
+const logger = require('../utils/logger');
 const { validationResult } = require('express-validator');
 
 
@@ -20,7 +21,7 @@ const saveAppointment = async (req, res) => {
         // Respond with success message if appointment data is successfully saved
         res.status(201).json({ message: 'Appointment saved successfully' });//, appointmentId: result.id 
     } catch (error) {
-        console.error('Error saving appointment:', error);
+        logger.error('Error saving appointment', { error: error.message, userId });
         res.status(500).json({ error: 'Internal server error' });
     }
 };
@@ -65,7 +66,7 @@ const saveAppointmentV2 = async (req, res) => {
       appointment,
     });
   } catch (error) {
-    console.error("Error saving appointment:", error);
+    logger.error('Error saving appointment (V2)', { error: error.message, userId });
     res.status(500).json({ error: "Internal server error" });
   }
 };
@@ -114,7 +115,7 @@ const updateAppointment = async (req,res)=>{
       appointment: updatedAppointment,
     });
   } catch (error) {
-    console.error('Error updating appointment:', error);
+    logger.error('Error updating appointment', { error: error.message, appointmentId: id });
     res.status(500).json({ error: 'Internal server error' });
   }
 }
@@ -133,7 +134,7 @@ const delAppointment = async (req,res)=>{
       message: 'Appointment deleted successfully',
     });
   } catch (error) {
-    console.error('Error deleting appointment:', error);
+    logger.error('Error deleting appointment', { error: error.message, appointmentId: id });
     res.status(500).json({ error: 'Internal server error' });
   }
 }
@@ -149,7 +150,7 @@ const getAppointments = async (req, res) => {
         // Respond with the retrieved appointment data
         res.status(200).json(appointments);
     } catch (error) {
-        console.error('Error retrieving appointments:', error);
+        logger.error('Error retrieving appointments', { error: error.message });
         res.status(500).json({ error: 'Internal server error' });
     }
 };
@@ -174,7 +175,7 @@ const getAppointmentsV2 = async (req, res) => {
       appointments
     });
   } catch (error) {
-    console.error("Error retrieving appointments:", error);
+    logger.error('Error retrieving appointments (V2)', { error: error.message });
     res.status(500).json({ error: "Internal server error" });
   }
 };
diff --git a/controller/authController.js b/controller/authController.js
index 63b4a173..320564ed 100644
--- a/controller/authController.js
+++ b/controller/authController.js
@@ -1,4 +1,5 @@
 const authService = require('../services/authService');
+const logger = require('../utils/logger');
 const { createClient } = require('@supabase/supabase-js');
 
 const supabase = createClient(
@@ -28,7 +29,7 @@ exports.register = async (req, res) => {
         res.status(201).json(result);
 
     } catch (error) {
-        console.error('Registration error:', error);
+        logger.error('Registration error', { error: error.message, email: req.body.email });
         res.status(400).json({
             success: false,
             error: error.message
@@ -61,7 +62,7 @@ exports.login = async (req, res) => {
         res.json(result);
 
     } catch (error) {
-        console.error('Login error:', error);
+        logger.error('Login error', { error: error.message, email: req.body.email });
         res.status(401).json({
             success: false,
             error: error.message
@@ -93,7 +94,7 @@ exports.refreshToken = async (req, res) => {
         res.json(result);
 
     } catch (error) {
-        console.error('Token refresh error:', error);
+        logger.error('Token refresh error', { error: error.message });
         res.status(401).json({
             success: false,
             error: error.message
@@ -113,7 +114,7 @@ exports.logout = async (req, res) => {
         res.json(result);
 
     } catch (error) {
-        console.error('Logout error:', error);
+        logger.error('Logout error', { error: error.message, userId: req.user?.userId });
         res.status(500).json({
             success: false,
             error: error.message
@@ -133,7 +134,7 @@ exports.logoutAll = async (req, res) => {
         res.json(result);
 
     } catch (error) {
-        console.error('Logout all error:', error);
+        logger.error('Logout all error', { error: error.message, userId: req.user?.userId });
         res.status(500).json({
             success: false,
             error: error.message
@@ -181,7 +182,7 @@ exports.getProfile = async (req, res) => {
         });
 
     } catch (error) {
-        console.error('Get profile error:', error);
+        logger.error('Get profile error', { error: error.message, userId: req.user?.userId });
         res.status(500).json({
             success: false,
             error: 'Internal server error'
@@ -210,7 +211,7 @@ exports.logLoginAttempt = async (req, res) => {
     ]);
 
     if (error) {
-        console.error('❌ Failed to insert login log:', error);
+        logger.error('Failed to insert login log', { error: error.message, email });
         return res.status(500).json({ error: 'Failed to log login attempt' });
     }
 
@@ -239,7 +240,7 @@ exports.sendSMSByEmail = async (req, res) => {
     const phone = data.contact_number;
     const verificationCode = Math.floor(100000 + Math.random() * 900000).toString();
 
-    console.log(`📨 [DEV] Verification code for ${phone}: ${verificationCode}`);
+    logger.info('[DEV] Verification code generated', { phone, verificationCode });
 
 
     return res.status(200).json({
@@ -247,7 +248,7 @@ exports.sendSMSByEmail = async (req, res) => {
       phone,
     });
   } catch (err) {
-    console.error('❌ Error sending SMS:', err);
+    logger.error('Error sending SMS', { error: err.message, email });
     return res.status(500).json({ error: 'Internal server error' });
   }
 };
diff --git a/controller/chatbotController.js b/controller/chatbotController.js
index b214bdc7..1ab0ef40 100644
--- a/controller/chatbotController.js
+++ b/controller/chatbotController.js
@@ -1,4 +1,5 @@
 const { addHistory, getHistory, deleteHistory } = require('../model/chatbotHistory');
+const logger = require('../utils/logger');
 const fetch = (...args) =>
   import('node-fetch').then(({default: fetch}) => fetch(...args));
 
@@ -46,7 +47,7 @@ const getChatResponse = async (req, res) => {
         responseText = result.msg;
       }
     } catch (aiError) {
-      console.error("Error connecting to AI server:", aiError);
+      logger.error('Error connecting to AI server', { error: aiError.message, userId: user_id });
       // Continue with fallback response
     }
 
@@ -54,7 +55,7 @@ const getChatResponse = async (req, res) => {
     try {
       await addHistory(user_id, user_input, responseText);
     } catch (dbError) {
-      console.error("Error storing chat history:", dbError);
+      logger.error('Error storing chat history', { error: dbError.message, userId: user_id });
     }
 
     // Return response to user
@@ -64,7 +65,7 @@ const getChatResponse = async (req, res) => {
     });
     
   } catch (error) {
-    console.error("Error in chatbot response:", error);
+    logger.error('Error in chatbot response', { error: error.message, userId: user_id });
     return res.status(500).json({
       error: "Internal server error"
     });
@@ -109,14 +110,14 @@ const addURL = async (req, res) => {
         result: result
       });
     } catch (aiError) {
-      console.error("Error connecting to AI server:", aiError);
+      logger.error('Error connecting to AI server', { error: aiError.message, urls });
       return res.status(503).json({
         error: "AI server unavailable"
       });
     }
     
   } catch (error) {
-    console.error("Error processing URL:", error);
+    logger.error('Error processing URL', { error: error.message });
     return res.status(500).json({
       error: "Internal server error"
     });
@@ -136,7 +137,7 @@ const addPDF = async (req, res) => {
       result: "This is dummy response"
     });
   } catch (error) {
-    console.error("Error in chatbot response:", error);
+    logger.error('Error processing PDF', { error: error.message });
     return res.status(500).json({
       error: "Internal server error",
       details: process.env.NODE_ENV === 'development' ? error.message : undefined
@@ -170,7 +171,7 @@ const getChatHistory = async (req, res) => {
       chat_history: history
     });
   } catch (error) {
-    console.error("Error retrieving chat history:", error);
+    logger.error('Error retrieving chat history', { error: error.message, userId: user_id });
     return res.status(500).json({
       error: "Internal server error",
       details: process.env.NODE_ENV === 'development' ? error.message : undefined
@@ -196,7 +197,7 @@ const clearChatHistory = async (req, res) => {
       message: "Chat history cleared successfully"
     });
   } catch (error) {
-    console.error("Error clearing chat history:", error);
+    logger.error('Error clearing chat history', { error: error.message, userId: user_id });
     return res.status(500).json({
       error: "Internal server error",
       details: process.env.NODE_ENV === 'development' ? error.message : undefined
diff --git a/controller/homeServiceController.js b/controller/homeServiceController.js
index b9136890..7e5bb22c 100644
--- a/controller/homeServiceController.js
+++ b/controller/homeServiceController.js
@@ -1,4 +1,5 @@
 const supabase = require("../dbConnection.js");
+const logger = require('../utils/logger');
 const {
   createServiceModel,
   updateServiceModel,
@@ -17,7 +18,7 @@ const getServiceContents = async (req, res) => {
       .select("title, description, image");
 
     if (error) {
-      console.error("Error get service contents:", error.message);
+      logger.error('Error getting service contents', { error: error.message });
       return res.status(500).json({ error: "Failed to get service contents" });
     }
 
@@ -25,7 +26,7 @@ const getServiceContents = async (req, res) => {
       .status(200)
       .json({ message: "Get service contents successfully", data });
   } catch (error) {
-    console.error("Internal server error:", error.message);
+    logger.error('Internal server error in getServiceContents', { error: error.message });
     return res.status(500).json({ error: "Internal server error" });
   }
 };
@@ -62,7 +63,7 @@ const getServiceContentsPage = async (req, res) => {
     const { data, error, count } = await query;
 
     if (error) {
-      console.error("Error getting service contents:", error.message);
+      logger.error('Error getting service contents', { error: error.message });
       return res.status(500).json({ error: "Failed to get service contents" });
     }
 
@@ -75,7 +76,7 @@ const getServiceContentsPage = async (req, res) => {
       data,
     });
   } catch (error) {
-    console.error("Internal server error:", error.message);
+    logger.error('Internal server error in getServiceContentsPage', { error: error.message });
     return res.status(500).json({ error: "Internal server error" });
   }
 };
@@ -100,7 +101,7 @@ const createService = async (req, res) => {
       data: service,
     });
   } catch (error) {
-    console.error("Error creating service:", error.message);
+    logger.error('Error creating service', { error: error.message });
     res.status(500).json({ error: error.message });
   }
 };
@@ -126,7 +127,7 @@ const updateService = async (req, res) => {
       data: service,
     });
   } catch (error) {
-    console.error("Error updating service:", error.message);
+    logger.error('Error updating service', { error: error.message, serviceId: req.params.id });
     res.status(500).json({ error: error.message });
   }
 };
@@ -145,7 +146,7 @@ const deleteService = async (req, res) => {
       message: "Service deleted successfully",
     });
   } catch (error) {
-    console.error("Error deleting service:", error.message);
+    logger.error('Error deleting service', { error: error.message, serviceId: req.params.id });
     res.status(500).json({ error: error.message });
   }
 };
@@ -167,7 +168,7 @@ const addSubscribe = async (req, res) => {
       data: subscribe,
     });
   } catch (error) {
-    console.error("Error creating subscribe:", error.message);
+    logger.error('Error creating subscribe', { error: error.message, email: req.body.email });
     res.status(500).json({ error: error.message });
   }
 };
diff --git a/controller/imageClassificationController.js b/controller/imageClassificationController.js
index 75600b73..16e673b4 100644
--- a/controller/imageClassificationController.js
+++ b/controller/imageClassificationController.js
@@ -1,12 +1,13 @@
 const fs = require('fs');
 const path = require('path');
+const logger = require('../utils/logger');
 const { executePythonScript } = require('../services/aiExecutionService');
 
 // Utility to delete the uploaded file
 const deleteFile = (filePath) => {
   fs.unlink(filePath, (err) => {
     if (err) {
-      console.error('Error deleting file:', err);
+      logger.error('Error deleting image file', { filePath, error: err.message });
     }
   });
 };
@@ -58,7 +59,7 @@ const predictImage = async (req, res) => {
       error: null
     });
   } catch (error) {
-    console.error('Error reading image file:', error);
+    logger.error('Error reading image file', { error: error.message, filePath: imagePath });
     return res.status(500).json({
       success: false,
       prediction: null,
diff --git a/controller/loginController.js b/controller/loginController.js
index 4c3f91c5..73fd70ec 100644
--- a/controller/loginController.js
+++ b/controller/loginController.js
@@ -1,5 +1,6 @@
 const bcrypt = require("bcryptjs");
 const jwt = require("jsonwebtoken");
+const logger = require('../utils/logger');
 const logLoginEvent = require("../Monitor_&_Logging/loginLogger");
 const getUserCredentials = require("../model/getUserCredentials.js");
 const { addMfaToken, verifyMfaToken } = require("../model/addMfaToken.js");
@@ -129,7 +130,7 @@ const login = async (req, res) => {
     return res.status(200).json({ user, token });
 
   } catch (err) {
-    console.error("Login error:", err);
+    logger.error('Login error', { error: err.message, email });
     return res.status(500).json({ error: "Internal server error" });
   }
 };
@@ -176,7 +177,7 @@ const loginMfa = async (req, res) => {
     return res.status(200).json({ user, token });
 
   } catch (err) {
-    console.error("MFA login error:", err);
+    logger.error('MFA login error', { error: err.message, email });
     return res.status(500).json({ error: "Internal server error" });
   }
 };
@@ -198,9 +199,9 @@ async function sendOtpEmail(email, token) {
         <p>– NutriHelp Security Team</p>
       `
     });
-    console.log("✅ OTP email sent successfully to", email);
+    logger.info('OTP email sent successfully', { email });
   } catch (err) {
-    console.error("Error sending OTP email:", err.message);
+    logger.error('Error sending OTP email', { error: err.message, email });
   }
 }
 
@@ -220,9 +221,9 @@ async function sendFailedLoginAlert(email, ip) {
         <p>– NutriHelp Security Team</p>
       `
     });
-    console.log(`✅ Failed login alert sent to ${email}`);
+    logger.info('Failed login alert sent', { email, ip });
   } catch (err) {
-    console.error("Failed to send alert email:", err.message);
+    logger.error('Failed to send alert email', { error: err.message, email });
   }
 }
 
diff --git a/controller/medicalPredictionController.js b/controller/medicalPredictionController.js
index 0811f5ab..adff2e5e 100644
--- a/controller/medicalPredictionController.js
+++ b/controller/medicalPredictionController.js
@@ -6,6 +6,7 @@
 // [TEMP-DB-OFF] keep imports for easy revert; safe to leave unused
 const { insertSurvey } = require("../model/healthSurveyModel");
 const { insertRiskReport } = require("../model/healthRiskReportModel");
+const logger = require('../utils/logger');
 
 const AI_RETRIEVE_URL =
   process.env.AI_RETRIEVE_URL ||
@@ -193,7 +194,7 @@ const predict = async (req, res) => {
       medical_report,
     });
   } catch (error) {
-    console.error("[predict] Unexpected error:", error);
+    logger.error('Unexpected error in medical prediction', { error: error.message });
     return res.status(500).json({ error: "Internal server error" });
   }
 };
diff --git a/controller/notificationController.js b/controller/notificationController.js
index c4ce8e19..89ddc1a7 100644
--- a/controller/notificationController.js
+++ b/controller/notificationController.js
@@ -1,4 +1,5 @@
 const supabase = require('../dbConnection.js');
+const logger = require('../utils/logger');
 
 // Create a new notification
 exports.createNotification = async (req, res) => {
@@ -13,7 +14,7 @@ exports.createNotification = async (req, res) => {
 
         res.status(201).json({ message: 'Notification created', notification: data });
     } catch (error) {
-        console.error('Error creating notification:', error);
+        logger.error('Error creating notification', { error: error.message, user_id: req.body.user_id });
         res.status(500).json({ error: 'An error occurred while creating the notification' });
     }
 };
@@ -36,7 +37,7 @@ exports.getNotificationsByUserId = async (req, res) => {
 
         res.status(200).json(data);
     } catch (error) {
-        console.error('Error retrieving notifications:', error);
+        logger.error('Error retrieving notifications', { error: error.message, user_id: req.params.user_id });
         res.status(500).json({ error: 'An error occurred while retrieving notifications' });
     }
 };
@@ -54,7 +55,7 @@ exports.updateNotificationStatusById = async (req, res) => {
             
 
         if (error) {
-            console.error('Error updating notification:', error);
+            logger.error('Error updating notification', { error: error.message, notificationId: id });
             return res.status(500).json({ error: 'Failed to update notification' });
         }
 
@@ -65,7 +66,7 @@ exports.updateNotificationStatusById = async (req, res) => {
 
         res.status(200).json({ message: 'Notification updated successfully', notification: data });
     } catch (error) {
-        console.error('Error updating notification:', error);
+        logger.error('Error updating notification', { error: error.message, notificationId: req.params.id });
         res.status(500).json({ error: 'An error occurred while updating the notification' });
     }
 };
@@ -82,7 +83,7 @@ exports.deleteNotificationById = async (req, res) => {
            
 
         if (error) {
-            console.error('Error deleting notification:', error);
+            logger.error('Error deleting notification', { error: error.message, notificationId: id });
             return res.status(500).json({ error: 'Failed to delete notification' });
         }
 
@@ -93,7 +94,7 @@ exports.deleteNotificationById = async (req, res) => {
 
         res.status(200).json({ message: 'Notification deleted successfully' });
     } catch (error) {
-        console.error('Error deleting notification:', error);
+        logger.error('Error deleting notification', { error: error.message, notificationId: req.params.id });
         res.status(500).json({ error: 'An error occurred while deleting the notification' });
     }
 };
@@ -121,7 +122,7 @@ exports.markAllUnreadNotificationsAsRead = async (req, res) => {
         
         res.status(200).json({ message: 'All unread notifications marked as read', updatedNotifications: data });
     } catch (error) {
-        console.error('Error marking notifications as read:', error);
+        logger.error('Error marking notifications as read', { error: error.message, user_id: req.params.user_id });
         res.status(500).json({ error: 'An error occurred while marking notifications as read' });
     }
 };
diff --git a/controller/uploadController.js b/controller/uploadController.js
index 04fb4780..5e8ed247 100644
--- a/controller/uploadController.js
+++ b/controller/uploadController.js
@@ -1,4 +1,5 @@
 const multer = require('multer');
+const logger = require('../utils/logger');
 const { createClient } = require('@supabase/supabase-js');
 
 const supabase = createClient(
@@ -76,7 +77,7 @@ exports.uploadFile = async (req, res) => {
 
       return res.status(201).json({ message: 'File uploaded successfully', fileUrl: fileUrl });
     } catch (error) {
-      console.error('❌ File upload failed:', error);
+      logger.error('File upload failed', { error: error.message, userId: req.user?.userId });
       return res.status(500).json({ error: 'File upload failed' });
     }
   });
diff --git a/controller/userPreferencesController.js b/controller/userPreferencesController.js
index fc7b5902..f99205c5 100644
--- a/controller/userPreferencesController.js
+++ b/controller/userPreferencesController.js
@@ -1,4 +1,5 @@
 const fetchUserPreferences = require("../model/fetchUserPreferences");
+const logger = require('../utils/logger');
 const updateUserPreferences = require("../model/updateUserPreferences");
 
 const getUserPreferences = async (req, res) => {
@@ -17,7 +18,7 @@ const getUserPreferences = async (req, res) => {
 
 		return res.status(200).json(userPreferences);
 	} catch (error) {
-		console.error(error);
+		logger.error('Error fetching user preferences', { error: error.message, userId: req.user?.userId });
 		return res.status(500).json({ error: "Internal server error" });
 	}
 };
@@ -31,7 +32,7 @@ const postUserPreferences = async (req, res) => {
 			.status(204)
 			.json({ message: "User preferences updated successfully" });
 	} catch (error) {
-		console.error(error);
+		logger.error('Error updating user preferences', { error: error.message, userId: req.body.user?.userId });
 		return res.status(500).json({ error: "Internal server error" });
 	}
 };
diff --git a/middleware/requestLogger.js b/middleware/requestLogger.js
new file mode 100644
index 00000000..8cf5bdbf
--- /dev/null
+++ b/middleware/requestLogger.js
@@ -0,0 +1,83 @@
+/**
+ * middleware/requestLogger.js
+ * 
+ * Structured request logging middleware
+ * Logs all incoming requests and responses
+ */
+
+const logger = require('../utils/logger');
+
+/**
+ * Generate unique request ID
+ */
+const generateRequestId = () => {
+  return `${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+};
+
+/**
+ * Main request logging middleware
+ */
+const requestLoggingMiddleware = (req, res, next) => {
+  // Generate and attach request ID
+  const requestId = req.headers['x-request-id'] || generateRequestId();
+  req.id = requestId;
+  
+  // Track request start time
+  const startTime = Date.now();
+
+  // Extract useful request info
+  const method = req.method;
+  const path = req.path;
+  const ip = req.ip || req.connection.remoteAddress;
+  const userAgent = req.headers['user-agent'] || 'unknown';
+  
+  // Log incoming request
+  logger.info(`→ ${method} ${path}`, {
+    requestId,
+    method,
+    path,
+    ip,
+    userAgent,
+    ...(req.user ? { userId: req.user.id } : {}),
+    query: Object.keys(req.query).length > 0 ? req.query : undefined
+  });
+
+  // Capture response details
+  const originalSend = res.send;
+  res.send = function(data) {
+    // Calculate duration
+    const duration = Date.now() - startTime;
+    const statusCode = res.statusCode;
+
+    // Determine log level based on status code
+    let logLevel = 'info';
+    if (statusCode >= 500) logLevel = 'error';
+    else if (statusCode >= 400) logLevel = 'warn';
+    else if (duration > 5000) logLevel = 'warn'; // Slow request
+
+    // Log response
+    const logMessage = `← ${method} ${path} ${statusCode} (${duration}ms)`;
+    
+    logger[logLevel](logMessage, {
+      requestId,
+      method,
+      path,
+      statusCode,
+      duration,
+      ...(req.user ? { userId: req.user.id } : {}),
+      contentLength: res.get('content-length'),
+      ...(logLevel === 'error' ? { responseBody: data } : {})
+    });
+
+    // Call original send
+    return originalSend.call(this, data);
+  };
+
+  // Attach logger to request for use in controllers
+  req.logger = logger;
+  req.requestId = requestId;
+
+  next();
+};
+
+module.exports = { requestLoggingMiddleware, generateRequestId };
diff --git a/middleware/structuredErrorHandler.js b/middleware/structuredErrorHandler.js
new file mode 100644
index 00000000..8e01851e
--- /dev/null
+++ b/middleware/structuredErrorHandler.js
@@ -0,0 +1,79 @@
+/**
+ * middleware/structuredErrorHandler.js
+ * 
+ * Centralized error handling with structured logging
+ * Should be used as the last middleware in Express
+ */
+
+const logger = require('../utils/logger');
+
+/**
+ * Structured error handling middleware
+ * Must be defined after all other middleware and routes
+ */
+const structuredErrorHandler = (err, req, res, next) => {
+  // Determine error status code
+  const statusCode = err.statusCode || err.status || 500;
+  const isClientError = statusCode >= 400 && statusCode < 500;
+  const isServerError = statusCode >= 500;
+
+  // Build error context
+  const errorContext = {
+    requestId: req.id || req.requestId,
+    userId: req.user?.id,
+    method: req.method,
+    path: req.path,
+    ip: req.ip,
+    statusCode,
+    errorType: err.constructor.name,
+    errorCode: err.code,
+    validation: err.validation, // For validation errors
+    details: err.details // Additional error details
+  };
+
+  // Log the error with appropriate level
+  if (isServerError) {
+    logger.error(`Server Error: ${err.message}`, {
+      ...errorContext,
+      stack: err.stack,
+      ...(err.originalError && { originalError: err.originalError })
+    });
+  } else if (isClientError) {
+    logger.warn(`Client Error: ${err.message}`, {
+      ...errorContext,
+      // Don't include stack trace for client errors
+    });
+  } else {
+    logger.info(`Error: ${err.message}`, errorContext);
+  }
+
+  // Send error response
+  res.status(statusCode).json({
+    success: false,
+    error: {
+      message: err.message,
+      code: err.code || 'INTERNAL_ERROR',
+      ...(process.env.NODE_ENV !== 'production' && { stack: err.stack })
+    },
+    requestId: req.id || req.requestId,
+    ...(process.env.NODE_ENV === 'development' && { details: err.details })
+  });
+};
+
+/**
+ * Custom error class for structured errors
+ */
+class AppError extends Error {
+  constructor(message, statusCode = 500, code = 'ERROR', details = {}) {
+    super(message);
+    this.statusCode = statusCode;
+    this.code = code;
+    this.details = details;
+    Error.captureStackTrace(this, this.constructor);
+  }
+}
+
+module.exports = {
+  structuredErrorHandler,
+  AppError
+};
diff --git a/package-lock.json b/package-lock.json
index 74a2579a..6244baa9 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -31,6 +31,7 @@
         "sinon": "18.0.0",
         "swagger-ui-express": "5.0.0",
         "twilio": "5.9.0",
+        "winston": "^3.11.0",
         "yamljs": "0.3.0"
       },
       "devDependencies": {
@@ -639,6 +640,26 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@colors/colors": {
+      "version": "1.6.0",
+      "resolved": "https://registry.npmjs.org/@colors/colors/-/colors-1.6.0.tgz",
+      "integrity": "sha512-Ir+AOibqzrIsL6ajt3Rz3LskB7OiMVHqltZmspbW/TJuTVuyOMirVqAkjfY6JISiLHgyNqicAC8AyHHGzNd/dA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.1.90"
+      }
+    },
+    "node_modules/@dabh/diagnostics": {
+      "version": "2.0.8",
+      "resolved": "https://registry.npmjs.org/@dabh/diagnostics/-/diagnostics-2.0.8.tgz",
+      "integrity": "sha512-R4MSXTVnuMzGD7bzHdW2ZhhdPC/igELENcq5IjEverBvq5hn1SXCWcsi6eSsdWP0/Ur+SItRRjAktmdoX/8R/Q==",
+      "license": "MIT",
+      "dependencies": {
+        "@so-ric/colorspace": "^1.1.6",
+        "enabled": "2.0.x",
+        "kuler": "^2.0.0"
+      }
+    },
     "node_modules/@emnapi/core": {
       "version": "1.7.1",
       "resolved": "https://registry.npmjs.org/@emnapi/core/-/core-1.7.1.tgz",
@@ -1497,6 +1518,16 @@
       "integrity": "sha512-DE427ROAphMQzU4ENbliGYrBSYPXF+TtLg9S8vzeA+OF4ZKzoDdzfL8sxuMUGS/lgRhM6j1URSk9ghf7Xo1tyA==",
       "license": "(Unlicense OR Apache-2.0)"
     },
+    "node_modules/@so-ric/colorspace": {
+      "version": "1.1.6",
+      "resolved": "https://registry.npmjs.org/@so-ric/colorspace/-/colorspace-1.1.6.tgz",
+      "integrity": "sha512-/KiKkpHNOBgkFJwu9sh48LkHSMYGyuTcSFK/qMBdnOAlrRJzRSXAOFB5qwzaVQuDl8wAvHVMkaASQDReTahxuw==",
+      "license": "MIT",
+      "dependencies": {
+        "color": "^5.0.2",
+        "text-hex": "1.0.x"
+      }
+    },
     "node_modules/@supabase/auth-js": {
       "version": "2.86.0",
       "resolved": "https://registry.npmjs.org/@supabase/auth-js/-/auth-js-2.86.0.tgz",
@@ -1709,6 +1740,12 @@
         "form-data": "^4.0.0"
       }
     },
+    "node_modules/@types/triple-beam": {
+      "version": "1.3.5",
+      "resolved": "https://registry.npmjs.org/@types/triple-beam/-/triple-beam-1.3.5.tgz",
+      "integrity": "sha512-6WaYesThRMCl19iryMYP7/x2OVgCtbIVflDGFpWnb9irXI3UjYE4AzmYuiUKY1AJstGijoY+MgUszMgRxIYTYw==",
+      "license": "MIT"
+    },
     "node_modules/@types/ws": {
       "version": "8.18.1",
       "resolved": "https://registry.npmjs.org/@types/ws/-/ws-8.18.1.tgz",
@@ -2173,6 +2210,12 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/async": {
+      "version": "3.2.6",
+      "resolved": "https://registry.npmjs.org/async/-/async-3.2.6.tgz",
+      "integrity": "sha512-htCUDlxyyCLMgaM3xXg0C0LW2xqfuQ6p05pCEIsXuyQ+a1koYKTuBMzRNwmybfLgvJDMd0r1LTn4+E0Ti6C2AA==",
+      "license": "MIT"
+    },
     "node_modules/asynckit": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/asynckit/-/asynckit-0.4.0.tgz",
@@ -2770,6 +2813,19 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/color": {
+      "version": "5.0.3",
+      "resolved": "https://registry.npmjs.org/color/-/color-5.0.3.tgz",
+      "integrity": "sha512-ezmVcLR3xAVp8kYOm4GS45ZLLgIE6SPAFoduLr6hTDajwb3KZ2F46gulK3XpcwRFb5KKGCSezCBAY4Dw4HsyXA==",
+      "license": "MIT",
+      "dependencies": {
+        "color-convert": "^3.1.3",
+        "color-string": "^2.1.3"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/color-convert": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
@@ -2790,6 +2846,27 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/color-string": {
+      "version": "2.1.4",
+      "resolved": "https://registry.npmjs.org/color-string/-/color-string-2.1.4.tgz",
+      "integrity": "sha512-Bb6Cq8oq0IjDOe8wJmi4JeNn763Xs9cfrBcaylK1tPypWzyoy2G3l90v9k64kjphl/ZJjPIShFztenRomi8WTg==",
+      "license": "MIT",
+      "dependencies": {
+        "color-name": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/color-string/node_modules/color-name": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/color-name/-/color-name-2.1.0.tgz",
+      "integrity": "sha512-1bPaDNFm0axzE4MEAzKPuqKWeRaT43U/hyxKPBdqTfmPF+d6n7FSoTFxLVULUJOmiLp01KjhIPPH+HrXZJN4Rg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=12.20"
+      }
+    },
     "node_modules/color-support": {
       "version": "1.1.3",
       "resolved": "https://registry.npmjs.org/color-support/-/color-support-1.1.3.tgz",
@@ -2798,6 +2875,27 @@
         "color-support": "bin.js"
       }
     },
+    "node_modules/color/node_modules/color-convert": {
+      "version": "3.1.3",
+      "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-3.1.3.tgz",
+      "integrity": "sha512-fasDH2ont2GqF5HpyO4w0+BcewlhHEZOFn9c1ckZdHpJ56Qb7MHhH/IcJZbBGgvdtwdwNbLvxiBEdg336iA9Sg==",
+      "license": "MIT",
+      "dependencies": {
+        "color-name": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=14.6"
+      }
+    },
+    "node_modules/color/node_modules/color-name": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/color-name/-/color-name-2.1.0.tgz",
+      "integrity": "sha512-1bPaDNFm0axzE4MEAzKPuqKWeRaT43U/hyxKPBdqTfmPF+d6n7FSoTFxLVULUJOmiLp01KjhIPPH+HrXZJN4Rg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=12.20"
+      }
+    },
     "node_modules/combined-stream": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/combined-stream/-/combined-stream-1.0.8.tgz",
@@ -3209,6 +3307,12 @@
       "integrity": "sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A==",
       "license": "MIT"
     },
+    "node_modules/enabled": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/enabled/-/enabled-2.0.0.tgz",
+      "integrity": "sha512-AKrN98kuwOzMIdAizXGI86UFBoo26CL21UM763y1h/GMSJ4/OHU9k2YlsmBpyScFo/wbLzWQJBMCW4+IO3/+OQ==",
+      "license": "MIT"
+    },
     "node_modules/encodeurl": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/encodeurl/-/encodeurl-1.0.2.tgz",
@@ -3492,6 +3596,12 @@
         "bser": "2.1.1"
       }
     },
+    "node_modules/fecha": {
+      "version": "4.2.3",
+      "resolved": "https://registry.npmjs.org/fecha/-/fecha-4.2.3.tgz",
+      "integrity": "sha512-OP2IUU6HeYKJi3i0z4A19kHMQoLVs4Hc+DPqqxI2h/DPZHTm/vjsfC6P0b4jCMy14XizLBqvndQ+UilD7707Jw==",
+      "license": "MIT"
+    },
     "node_modules/fetch-blob": {
       "version": "3.2.0",
       "resolved": "https://registry.npmjs.org/fetch-blob/-/fetch-blob-3.2.0.tgz",
@@ -3587,6 +3697,12 @@
         "flat": "cli.js"
       }
     },
+    "node_modules/fn.name": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/fn.name/-/fn.name-1.1.0.tgz",
+      "integrity": "sha512-GRnmB5gPyJpAhTQdSZTSp9uaPSvl09KoYcMQtsB9rQoOmzs9dH6ffeccH+Z+cv6P68Hu5bC6JjRh4Ah/mHSNRw==",
+      "license": "MIT"
+    },
     "node_modules/follow-redirects": {
       "version": "1.15.11",
       "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.15.11.tgz",
@@ -4333,7 +4449,6 @@
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/is-stream/-/is-stream-2.0.1.tgz",
       "integrity": "sha512-hFoiJiTl63nn+kstHGBtewWSKnQLpyb155KHheA1l39uvtO9nWIop1p3udqPcUd/xbF1VLMO4n7OI6p7RbngDg==",
-      "dev": true,
       "license": "MIT",
       "engines": {
         "node": ">=8"
@@ -5193,6 +5308,12 @@
         "safe-buffer": "^5.0.1"
       }
     },
+    "node_modules/kuler": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/kuler/-/kuler-2.0.0.tgz",
+      "integrity": "sha512-Xq9nH7KlWZmXAtodXDDRE7vs6DU1gTU8zYDHDiWLSip45Egwq3plLHzPn27NgvzL2r1LMPC1vdqh98sQxtqj4A==",
+      "license": "MIT"
+    },
     "node_modules/leven": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/leven/-/leven-3.1.0.tgz",
@@ -5291,6 +5412,29 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/logform": {
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/logform/-/logform-2.7.0.tgz",
+      "integrity": "sha512-TFYA4jnP7PVbmlBIfhlSe+WKxs9dklXMTEGcBCIvLhE/Tn3H6Gk1norupVW7m5Cnd4bLcr08AytbyV/xj7f/kQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@colors/colors": "1.6.0",
+        "@types/triple-beam": "^1.3.2",
+        "fecha": "^4.2.0",
+        "ms": "^2.1.1",
+        "safe-stable-stringify": "^2.3.1",
+        "triple-beam": "^1.3.0"
+      },
+      "engines": {
+        "node": ">= 12.0.0"
+      }
+    },
+    "node_modules/logform/node_modules/ms": {
+      "version": "2.1.3",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
+      "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==",
+      "license": "MIT"
+    },
     "node_modules/long": {
       "version": "5.3.2",
       "resolved": "https://registry.npmjs.org/long/-/long-5.3.2.tgz",
@@ -6012,6 +6156,15 @@
         "wrappy": "1"
       }
     },
+    "node_modules/one-time": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/one-time/-/one-time-1.0.0.tgz",
+      "integrity": "sha512-5DXOiRKwuSEcQ/l0kGCF6Q3jcADFv5tSmRaJck/OqkVFcOzutB134KRSfF0xDrL39MNnqxbHBbUUcjZIhTgb2g==",
+      "license": "MIT",
+      "dependencies": {
+        "fn.name": "1.x.x"
+      }
+    },
     "node_modules/onetime": {
       "version": "5.1.2",
       "resolved": "https://registry.npmjs.org/onetime/-/onetime-5.1.2.tgz",
@@ -6601,6 +6754,15 @@
       ],
       "license": "MIT"
     },
+    "node_modules/safe-stable-stringify": {
+      "version": "2.5.0",
+      "resolved": "https://registry.npmjs.org/safe-stable-stringify/-/safe-stable-stringify-2.5.0.tgz",
+      "integrity": "sha512-b3rppTKm9T+PsVCBEOUR46GWI7fdOs00VKZ1+9c1EWDaDMvjQc6tUwuFyIprgGgTcWoVHSKrU8H31ZHA2e0RHA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/safer-buffer": {
       "version": "2.1.2",
       "resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
@@ -6904,6 +7066,15 @@
         "node": ">= 0.6"
       }
     },
+    "node_modules/stack-trace": {
+      "version": "0.0.10",
+      "resolved": "https://registry.npmjs.org/stack-trace/-/stack-trace-0.0.10.tgz",
+      "integrity": "sha512-KGzahc7puUKkzyMt+IqAep+TVNbKP+k2Lmwhub39m1AsTSkaDutx56aDCo+HLDzf/D26BIHTJWNiTG1KAJiQCg==",
+      "license": "MIT",
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/stack-utils": {
       "version": "2.0.6",
       "resolved": "https://registry.npmjs.org/stack-utils/-/stack-utils-2.0.6.tgz",
@@ -7336,6 +7507,12 @@
         "node": "*"
       }
     },
+    "node_modules/text-hex": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/text-hex/-/text-hex-1.0.0.tgz",
+      "integrity": "sha512-uuVGNWzgJ4yhRaNSiubPY7OjISw4sw4E5Uv0wbjp+OzcbmVU/rsT8ujgcXJhn9ypzsgr5vlzpPqP+MBBKcGvbg==",
+      "license": "MIT"
+    },
     "node_modules/time-span": {
       "version": "5.1.0",
       "resolved": "https://registry.npmjs.org/time-span/-/time-span-5.1.0.tgz",
@@ -7407,6 +7584,15 @@
         "tree-kill": "cli.js"
       }
     },
+    "node_modules/triple-beam": {
+      "version": "1.4.1",
+      "resolved": "https://registry.npmjs.org/triple-beam/-/triple-beam-1.4.1.tgz",
+      "integrity": "sha512-aZbgViZrg1QNcG+LULa7nhZpJTZSLm/mXnHXnbAbjmN5aSa0y7V+wvv6+4WaBtpISJzThKy+PIPxc1Nq1EJ9mg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 14.0.0"
+      }
+    },
     "node_modules/tslib": {
       "version": "2.8.1",
       "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.8.1.tgz",
@@ -7676,6 +7862,70 @@
         "string-width": "^1.0.2 || 2 || 3 || 4"
       }
     },
+    "node_modules/winston": {
+      "version": "3.11.0",
+      "resolved": "https://registry.npmjs.org/winston/-/winston-3.11.0.tgz",
+      "integrity": "sha512-L3yR6/MzZAOl0DsysUXHVjOwv8mKZ71TrA/41EIduGpOOV5LQVodqN+QdQ6BS6PJ/RdIshZhq84P/fStEZkk7g==",
+      "license": "MIT",
+      "dependencies": {
+        "@colors/colors": "^1.6.0",
+        "@dabh/diagnostics": "^2.0.2",
+        "async": "^3.2.3",
+        "is-stream": "^2.0.0",
+        "logform": "^2.4.0",
+        "one-time": "^1.0.0",
+        "readable-stream": "^3.4.0",
+        "safe-stable-stringify": "^2.3.1",
+        "stack-trace": "0.0.x",
+        "triple-beam": "^1.3.0",
+        "winston-transport": "^4.5.0"
+      },
+      "engines": {
+        "node": ">= 12.0.0"
+      }
+    },
+    "node_modules/winston-transport": {
+      "version": "4.9.0",
+      "resolved": "https://registry.npmjs.org/winston-transport/-/winston-transport-4.9.0.tgz",
+      "integrity": "sha512-8drMJ4rkgaPo1Me4zD/3WLfI/zPdA9o2IipKODunnGDcuqbHwjsbB79ylv04LCGGzU0xQ6vTznOMpQGaLhhm6A==",
+      "license": "MIT",
+      "dependencies": {
+        "logform": "^2.7.0",
+        "readable-stream": "^3.6.2",
+        "triple-beam": "^1.3.0"
+      },
+      "engines": {
+        "node": ">= 12.0.0"
+      }
+    },
+    "node_modules/winston-transport/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
+    "node_modules/winston/node_modules/readable-stream": {
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.2.tgz",
+      "integrity": "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA==",
+      "license": "MIT",
+      "dependencies": {
+        "inherits": "^2.0.3",
+        "string_decoder": "^1.1.1",
+        "util-deprecate": "^1.0.1"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
     "node_modules/workerpool": {
       "version": "9.3.4",
       "resolved": "https://registry.npmjs.org/workerpool/-/workerpool-9.3.4.tgz",
diff --git a/package.json b/package.json
index 651a13fe..9d26bcb8 100644
--- a/package.json
+++ b/package.json
@@ -46,6 +46,7 @@
     "sinon": "18.0.0",
     "swagger-ui-express": "5.0.0",
     "twilio": "5.9.0",
+    "winston": "^3.11.0",
     "yamljs": "0.3.0"
   },
   "devDependencies": {
diff --git a/server.js b/server.js
index b1c8ffd1..d385836a 100644
--- a/server.js
+++ b/server.js
@@ -1,5 +1,10 @@
 require("dotenv").config();
 
+// Structured Logging - NEW
+const logger = require('./utils/logger');
+const { requestLoggingMiddleware } = require('./middleware/requestLogger');
+const { structuredErrorHandler } = require('./middleware/structuredErrorHandler');
+
 //Logging & Metrics
 const {
   metricsMiddleware,
@@ -74,8 +79,8 @@ const port = process.env.PORT || 80;
 // DB
 let db = require("./dbConnection");
 
-// System routes
-app.use("/api/system", systemRoutes);
+// ⚠️ CRITICAL: Add request logging middleware FIRST, before any routes
+app.use(requestLoggingMiddleware);
 
 // CORS
 app.use(
@@ -146,6 +151,9 @@ app.use(express.urlencoded({ limit: "50mb", extended: true }));
 app.use(metricsMiddleware);
 app.get("/metrics", metricsEndpoint);
 
+// System routes (early in chain)
+app.use("/api/system", systemRoutes);
+
 // Main routes registrar
 const routes = require("./routes");
 routes(app);
@@ -161,20 +169,8 @@ app.use("/security", securityEventsRoutes);
 // Error handler
 app.use(errorLogger);
 
-// Final error handler
-app.use((err, req, res, next) => {
-  const status = err.status || 500;
-  const message =
-    process.env.NODE_ENV === "production"
-      ? "Internal Server Error"
-      : err.message;
-
-  res.status(status).json({
-    success: false,
-    error: message,
-    timestamp: new Date().toISOString(),
-  });
-});
+// Structured error handling middleware (MUST be last)
+app.use(structuredErrorHandler);
 
 // Global error handler
 const {
diff --git a/utils/logger.js b/utils/logger.js
new file mode 100644
index 00000000..60d4d266
--- /dev/null
+++ b/utils/logger.js
@@ -0,0 +1,163 @@
+/**
+ * utils/logger.js
+ * 
+ * Centralized structured logging using Winston
+ * 
+ * Usage:
+ *   const logger = require('../utils/logger');
+ *   logger.info('User logged in', { userId: 123, email: 'user@example.com' });
+ *   logger.error('Database error', { error: err, query: sql });
+ *   logger.warn('Rate limit approaching', { userId: 123, limit: 1000 });
+ */
+
+const winston = require('winston');
+const path = require('path');
+const fs = require('fs');
+
+// Ensure logs directory exists
+const logsDir = path.join(process.cwd(), 'logs');
+if (!fs.existsSync(logsDir)) {
+  fs.mkdirSync(logsDir, { recursive: true });
+}
+
+/**
+ * Custom format for structured logging
+ */
+const customFormat = winston.format.combine(
+  winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss' }),
+  winston.format.errors({ stack: true }),
+  winston.format.json(),
+  // Custom printf for console (more readable)
+  winston.format.printf(({ timestamp, level, message, requestId, userId, ...meta }) => {
+    let baseLog = `${timestamp} [${level.toUpperCase()}]`;
+    
+    if (requestId) baseLog += ` [REQ:${requestId}]`;
+    if (userId) baseLog += ` [USER:${userId}]`;
+    
+    baseLog += ` ${message}`;
+    
+    // Add metadata if present
+    if (Object.keys(meta).length > 0) {
+      // Filter out the symbol used by winston
+      const cleanMeta = Object.fromEntries(
+        Object.entries(meta).filter(([key]) => !key.startsWith('Symbol'))
+      );
+      if (Object.keys(cleanMeta).length > 0) {
+        baseLog += ` ${JSON.stringify(cleanMeta)}`;
+      }
+    }
+    
+    return baseLog;
+  })
+);
+
+/**
+ * Create logger with Winston
+ */
+const logger = winston.createLogger({
+  level: process.env.LOG_LEVEL || (process.env.NODE_ENV === 'production' ? 'info' : 'debug'),
+  format: customFormat,
+  defaultMeta: {
+    service: 'nutrihelp-api',
+    environment: process.env.NODE_ENV || 'development'
+  },
+  transports: [
+    // Console output (always)
+    new winston.transports.Console({
+      level: process.env.NODE_ENV === 'production' ? 'info' : 'debug',
+      format: winston.format.combine(
+        winston.format.colorize(),
+        winston.format.printf(({ timestamp, level, message, requestId, userId, ...meta }) => {
+          let output = `${timestamp} ${level} `;
+          if (requestId) output += `(${requestId}) `;
+          if (userId) output += `[${userId}] `;
+          output += message;
+          
+          if (Object.keys(meta).length > 0) {
+            const cleanMeta = Object.fromEntries(
+              Object.entries(meta).filter(([key]) => !key.startsWith('Symbol'))
+            );
+            if (Object.keys(cleanMeta).length > 0) {
+              output += ` ${JSON.stringify(cleanMeta, null, 2)}`;
+            }
+          }
+          return output;
+        })
+      )
+    }),
+
+    // File logging - all logs
+    new winston.transports.File({
+      filename: path.join(logsDir, 'app.log'),
+      maxsize: 10485760, // 10MB
+      maxFiles: 5,
+      format: winston.format.json()
+    }),
+
+    // File logging - errors only
+    new winston.transports.File({
+      filename: path.join(logsDir, 'error.log'),
+      level: 'error',
+      maxsize: 10485760,
+      maxFiles: 10,
+      format: winston.format.json()
+    }),
+
+    // File logging - requests (if in production)
+    ...(process.env.NODE_ENV === 'production' ? [
+      new winston.transports.File({
+        filename: path.join(logsDir, 'requests.log'),
+        maxsize: 10485760,
+        maxFiles: 5,
+        format: winston.format.json()
+      })
+    ] : [])
+  ]
+});
+
+/**
+ * Log levels:
+ * error (0): Something failed
+ * warn (1):  Something concerning but not fatal
+ * info (2):  General information
+ * http (3): HTTP requests/responses
+ * debug (4): Detailed debugging information
+ */
+
+/**
+ * Helper to create error log with standard format
+ */
+logger.logError = (message, error, context = {}) => {
+  logger.error(message, {
+    error: {
+      message: error?.message,
+      code: error?.code,
+      stack: error?.stack
+    },
+    ...context
+  });
+};
+
+/**
+ * Helper to create HTTP log with standard format
+ */
+logger.logHttpRequest = (method, path, statusCode, duration, context = {}) => {
+  logger.info(`${method} ${path} - ${statusCode}`, {
+    http: {
+      method,
+      path,
+      statusCode,
+      duration: `${duration}ms`
+    },
+    ...context
+  });
+};
+
+/**
+ * Helper for database operations
+ */
+logger.logDB = (operation, table, context = {}) => {
+  logger.debug(`DB: ${operation} on ${table}`, context);
+};
+
+module.exports = logger;