feat: add welcome email to be sent to new registering user

README.md

@@ -113,6 +113,18 @@ JWT_SECRET=your-secret-key
 GEMINI_API_KEY=your-gemini-api-key
 ```
 
+For welcome email setup:
+```env
+SENDGRID_API_KEY=SG.your-sendgrid-api-key
+EMAIL_FROM="Paisable <no-reply@paisable.com>"
+
+EMAIL_USER=your@gmail.com
+EMAIL_PASS=your-app-password
+SMTP_HOST=smtp.gmail.com
+SMTP_PORT=587
+SMTP_SECURE=false
+```
+
 Start the backend:
 
 ```bash

backend/controllers/authController.js

@@ -1,6 +1,7 @@
 const User = require('../models/User');
 const jwt = require('jsonwebtoken');
 const bcrypt = require('bcryptjs');
+const { sendWelcomeEmail } = require('../utils/sendEmail');
 
 // Function to generate JWT
 const generateToken = (id) => {
@@ -37,6 +38,13 @@ const signup = async (req, res) => {
         email: user.email,
         token: generateToken(user._id),
       });
+
+      // sends welcome email
+      sendWelcomeEmail(user.email, user.name || '')
+        .then(() => console.log('Welcome email sent to', user.email))
+        .catch(err => console.error('Welcome email failed for', user.email, err && err.message));
+
+
     } else {
       res.status(400).json({ message: 'Invalid user data' });
     }

backend/package.json

@@ -15,6 +15,7 @@
   },
   "dependencies": {
     "@google/generative-ai": "^0.24.1",
+    "@sendgrid/mail": "^8.1.6",
     "bcryptjs": "^3.0.2",
     "cors": "^2.8.5",
     "dotenv": "^17.2.2",
@@ -24,6 +25,7 @@
     "mongodb": "^6.19.0",
     "mongoose": "^8.18.1",
     "multer": "^2.0.2",
+    "nodemailer": "^7.0.6",
     "papaparse": "^5.5.3"
   },
   "devDependencies": {

backend/utils/sendEmail.js

@@ -0,0 +1,108 @@
+require("dotenv").config();
+
+let sendRaw;
+
+// Validate critical env vars
+if (!process.env.SENDGRID_API_KEY && (!process.env.EMAIL_USER || !process.env.EMAIL_PASS)) {
+  console.warn(
+    "Warning: No email provider fully configured. Emails may fail to send. " +
+    "Set SENDGRID_API_KEY for SendGrid or EMAIL_USER/EMAIL_PASS for SMTP."
+  );
+}
+
+const emailFrom = process.env.EMAIL_FROM || process.env.EMAIL_USER || "no-reply@paisable.com";
+
+// Use SendGrid if API key is available
+if (process.env.SENDGRID_API_KEY) {
+  const sgMail = require("@sendgrid/mail");
+  sgMail.setApiKey(process.env.SENDGRID_API_KEY);
+
+  sendRaw = async ({ to, from, subject, text, html }) => {
+    try {
+      const msg = {
+        to,
+        from: from || emailFrom,
+        subject,
+        text,
+        html,
+      };
+      return await sgMail.send(msg);
+    } catch (err) {
+      console.error("SendGrid email failed", { to, subject, message: err.message });
+    }
+  };
+} else {
+  // Fallback to SMTP via Nodemailer
+  const nodemailer = require("nodemailer");
+
+  const transport = nodemailer.createTransport({
+    host: process.env.SMTP_HOST || "smtp.gmail.com",
+    port: process.env.SMTP_PORT ? Number(process.env.SMTP_PORT) : 587,
+    secure: process.env.SMTP_SECURE === "true",
+    auth: {
+      user: process.env.EMAIL_USER,
+      pass: process.env.EMAIL_PASS,
+    },
+    pool: true,
+    maxConnections: 5,
+    maxMessages: 100,
+  });
+
+  transport.verify()
+    .then(() => console.info("SMTP transporter verified"))
+    .catch(err => console.warn("SMTP transporter verification failed", { message: err.message }));
+
+  sendRaw = async ({ to, from, subject, text, html }) => {
+    try {
+      const mailOptions = {
+        from: from || emailFrom,
+        to,
+        subject,
+        text,
+        html,
+      };
+      return await transport.sendMail(mailOptions);
+    } catch (err) {
+      console.error("SMTP email failed", { to, subject, message: err.message });
+    }
+  };
+}
+
+// Inline welcome email template
+function renderWelcomeTemplate(name = "") {
+  const html = `
+    <div style="font-family: Arial, sans-serif; line-height:1.4; color:#333;">
+      <h2>Welcome to Paisable${name ? ", " + name : ""}!</h2>
+      <p>Thank you for creating an account. We're excited to have you on board.</p>
+      <p>Here are a few things to get started:</p>
+      <ul>
+        <li>Log in and complete your profile</li>
+        <li>Explore transactions and receipts</li>
+        <li>Contact support if you need help</li>
+      </ul>
+      <p>Cheers,<br/>The Paisable Team</p>
+    </div>
+  `;
+
+  const text = `Hi ${name}\n\nWelcome to Paisable! Your account has been created.\n\n- Log in and complete your profile\n- Explore transactions and receipts\n- Contact support if you need help\n\nCheers,\nThe Paisable Team`;
+
+  return { html, text };
+}
+
+// Fire-and-forget welcome email
+async function sendWelcomeEmail(to, name = "") {
+  if (!to) return;
+  const { html, text } = renderWelcomeTemplate(name);
+  const subject = "Welcome to Paisable!";
+  try {
+    await sendRaw({ to, subject, text, html });
+    console.info("Welcome email sent", { to });
+  } catch (err) {
+    console.error("Failed to send welcome email", { to, message: err.message });
+  }
+}
+
+module.exports = {
+  sendWelcomeEmail,
+  sendRaw,
+};