vansh1293 · Copilot · Apr 7, 2026 · Apr 7, 2026
diff --git a/README.md b/README.md
@@ -78,6 +78,7 @@ A huge shoutout to [Tashif Khan](https://github.com/Tashifkhan) for generously p
 
 - Customizable notification timing (1 hour, 1 day before)
 - Multiple reminder types: browser notifications, email alerts
+- One-click unsubscribe link in contest update emails
 - Contest difficulty and duration-based filtering
 - Time zone intelligent scheduling
 

diff --git a/emails/ContestEmail.tsx b/emails/ContestEmail.tsx
@@ -13,6 +13,10 @@ import {
 import * as React from "react";
 import { Contest } from "@/model/Contest";
 
+type ContestEmailProps = Contest & {
+    unsubscribeUrl?: string;
+};
+
 const platformStyles = {
     LeetCode: {
         color: "text-yellow-600",
@@ -52,7 +56,8 @@ export default function ContestEmail({
     endTime,
     duration,
     url,
-}: Contest) {
+    unsubscribeUrl,
+}: ContestEmailProps) {
     const theme = platformStyles[platform as keyof typeof platformStyles];
     return (
         <Html>
@@ -88,10 +93,17 @@ export default function ContestEmail({
                             <Text className="text-xs text-gray-500 mt-6">
                                 You’re receiving this email because you opted in for contest alerts.
                             </Text>
+                            {unsubscribeUrl && (
+                                <Text className="text-xs text-gray-500 mt-2">
+                                    <Link href={unsubscribeUrl} className="underline text-gray-600">
+                                        Unsubscribe from contest emails
+                                    </Link>
+                                </Text>
+                            )}
                         </Section>
                     </Container>
                 </Body>
             </Tailwind>
         </Html>
     );
-}
+}
diff --git a/src/app/api/unsubscribe-contest/route.ts b/src/app/api/unsubscribe-contest/route.ts
@@ -0,0 +1,56 @@
+import dbConnect from "@/lib/dbConnect";
+import { isValidUnsubscribeToken } from "@/lib/unsubscribeToken";
+import UserModel from "@/model/User";
+
+export async function GET(req: Request) {
+  try {
+    await dbConnect();
+
+    const { searchParams } = new URL(req.url);
+    const userId = searchParams.get("userId");
+    const token = searchParams.get("token");
+
+    if (!userId || !token || !isValidUnsubscribeToken(userId, token)) {
+      return new Response(
+        `<html><body style="font-family:sans-serif;padding:24px;"><h2>Invalid unsubscribe link</h2><p>Please sign in and update your notification settings manually.</p></body></html>`,
+        {
+          status: 400,
+          headers: { "Content-Type": "text/html; charset=utf-8" },
+        }
+      );
+    }
+
+    const updatedUser = await UserModel.findByIdAndUpdate(
+      userId,
+      { emailNotifications: false },
+      { new: true }
+    );
+
+    if (!updatedUser) {
+      return new Response(
+        `<html><body style="font-family:sans-serif;padding:24px;"><h2>User not found</h2><p>This unsubscribe link is no longer valid.</p></body></html>`,
+        {
+          status: 404,
+          headers: { "Content-Type": "text/html; charset=utf-8" },
+        }
+      );
+    }
+
+    return new Response(
+      `<html><body style="font-family:sans-serif;padding:24px;"><h2>Unsubscribed successfully</h2><p>You will no longer receive contest update emails.</p></body></html>`,
+      {
+        status: 200,
+        headers: { "Content-Type": "text/html; charset=utf-8" },
+      }
+    );
+  } catch (error) {
+    console.error("Error unsubscribing from contest emails:", error);
+    return new Response(
+      `<html><body style="font-family:sans-serif;padding:24px;"><h2>Unable to unsubscribe</h2><p>Please try again later.</p></body></html>`,
+      {
+        status: 500,
+        headers: { "Content-Type": "text/html; charset=utf-8" },
+      }
+    );
+  }
+}
diff --git a/src/helpers/sendContestDetails.ts b/src/helpers/sendContestDetails.ts
@@ -7,23 +7,22 @@ import UserModel from '@/model/User';
 import { Contest } from '@/model/Contest';
 import * as React from 'react';
 import ContestEmail from '../../emails/ContestEmail';
+import { createUnsubscribeToken } from '@/lib/unsubscribeToken';
 
 interface MailOptions {
     from: string | undefined;
-    to: string[];
+    to: string;
     subject: string;
     html: string;
 }
 export async function sendContestDetails(contestDetails: Contest[]): Promise<ApiResponse> {
     try {
         console.log("📧 Sending contest details...");
         await dbConnect();
-        const usersLeetCode = await UserModel.find({ LeetCode: true, emailNotifications: true });
-        const usersCodeForces = await UserModel.find({ CodeForces: true, emailNotifications: true });
-        const usersCodeChef = await UserModel.find({ CodeChef: true, emailNotifications: true });
-        const emails_leetcode = usersLeetCode.map(user => user.email);
-        const emails_codeforces = usersCodeForces.map(user => user.email);
-        const emails_codechef = usersCodeChef.map(user => user.email);
+        const usersLeetCode = await UserModel.find({ LeetCode: true, emailNotifications: true }).select('_id email');
+        const usersCodeForces = await UserModel.find({ CodeForces: true, emailNotifications: true }).select('_id email');
+        const usersCodeChef = await UserModel.find({ CodeChef: true, emailNotifications: true }).select('_id email');
+        const appUrl = process.env.NEXTAUTH_URL || process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000';
         const transporter = nodemailer.createTransport({
             service: 'gmail',
             auth: {
@@ -32,25 +31,32 @@ export async function sendContestDetails(contestDetails: Contest[]): Promise<Api
             }
         });
         for (const contest of contestDetails) {
-            const emails: string[] = [];
+            let recipients: { _id: string; email: string }[] = [];
             if (contest.platform === 'LeetCode') {
-                emails.push(...emails_leetcode);
+                recipients = usersLeetCode.map((user) => ({ _id: String(user._id), email: user.email }));
             } else if (contest.platform === 'CodeForces') {
-                emails.push(...emails_codeforces);
+                recipients = usersCodeForces.map((user) => ({ _id: String(user._id), email: user.email }));
             } else if (contest.platform === 'CodeChef') {
-                emails.push(...emails_codechef);
+                recipients = usersCodeChef.map((user) => ({ _id: String(user._id), email: user.email }));
             }
-            const htmlcontent = await render(React.createElement(ContestEmail, { ...contest }));
-            const mailOptions: MailOptions = {
-                from: process.env.NODEMAILER_EMAIL,
-                to: emails,
-                subject: 'Contest Update',
-                html: htmlcontent
-            };
-            try {
-                await transporter.sendMail(mailOptions);
-            } catch (err) {
-                console.error(`❌ Failed to send mail for contest "${contest.name}":`, err);
+
+            for (const user of recipients) {
+                const token = createUnsubscribeToken(user._id);
+                const unsubscribeUrl = token
+                    ? `${appUrl}/api/unsubscribe-contest?userId=${encodeURIComponent(user._id)}&token=${token}`
+                    : undefined;
+                const htmlcontent = await render(React.createElement(ContestEmail, { ...contest, unsubscribeUrl }));
+                const mailOptions: MailOptions = {
+                    from: process.env.NODEMAILER_EMAIL,
+                    to: user.email,
+                    subject: 'Contest Update',
+                    html: htmlcontent
+                };
+                try {
+                    await transporter.sendMail(mailOptions);
+                } catch (err) {
+                    console.error(`❌ Failed to send mail for contest "${contest.name}" to "${user.email}":`, err);
+                }
             }
         }
         return {
@@ -64,4 +70,4 @@ export async function sendContestDetails(contestDetails: Contest[]): Promise<Api
             message: "Failed to send contest details.",
         };
     }
-}
+}
diff --git a/src/lib/unsubscribeToken.ts b/src/lib/unsubscribeToken.ts
@@ -0,0 +1,25 @@
+import { createHmac, timingSafeEqual } from "crypto";
+
+const getUnsubscribeSecret = () => process.env.NEXTAUTH_SECRET;
+
+export const createUnsubscribeToken = (userId: string) => {
+  const secret = getUnsubscribeSecret();
+  if (!secret) return null;
+
+  return createHmac("sha256", secret).update(userId).digest("hex");
+};
+
+export const isValidUnsubscribeToken = (userId: string, token: string) => {
+  const secret = getUnsubscribeSecret();
+  if (!secret || !token) return false;
+
+  const expectedToken = createHmac("sha256", secret).update(userId).digest("hex");
+  const expectedBuffer = Buffer.from(expectedToken);
+  const tokenBuffer = Buffer.from(token);
+
+  if (expectedBuffer.length !== tokenBuffer.length) {
+    return false;
+  }
+
+  return timingSafeEqual(expectedBuffer, tokenBuffer);
+};