diff --git a/frontend/app/api/sessions/activity/route.ts b/frontend/app/api/sessions/activity/route.ts
index 354204e2..8e92c844 100644
--- a/frontend/app/api/sessions/activity/route.ts
+++ b/frontend/app/api/sessions/activity/route.ts
@@ -5,8 +5,11 @@ import { NextResponse } from 'next/server';
 
 import { db } from '@/db';
 import { activeSessions } from '@/db/schema/sessions';
+import { getRedisClient } from '@/lib/redis';
 
 const SESSION_TIMEOUT_MINUTES = 15;
+const SESSION_TIMEOUT_MS = SESSION_TIMEOUT_MINUTES * 60 * 1000;
+const REDIS_KEY = 'online_sessions';
 
 function getHeartbeatThrottleMs(): number {
   const raw = process.env.HEARTBEAT_THROTTLE_MS;
@@ -17,8 +20,59 @@ function getHeartbeatThrottleMs(): number {
   return Math.max(floor, parsed);
 }
 
-export async function POST() {
+async function heartbeatViaRedis(sessionId: string): Promise<number | null> {
+  const redis = getRedisClient();
+  if (!redis) return null;
+
   try {
+    const now = Date.now();
+    const pipeline = redis.pipeline();
+    pipeline.zadd(REDIS_KEY, { score: now, member: sessionId });
+    pipeline.zremrangebyscore(REDIS_KEY, '-inf', now - SESSION_TIMEOUT_MS);
+    pipeline.zcard(REDIS_KEY);
+
+    const results = await pipeline.exec();
+    return results[2] as number;
+  } catch (err) {
+    console.warn('Redis heartbeat failed, falling back to DB:', err);
+    return null;
+  }
+}
+
+async function heartbeatViaDb(sessionId: string): Promise<number> {
+  const now = new Date();
+  const heartbeatThreshold = new Date(
+    now.getTime() - getHeartbeatThrottleMs()
+  );
+
+  await db
+    .insert(activeSessions)
+    .values({ sessionId, lastActivity: now })
+    .onConflictDoUpdate({
+      target: activeSessions.sessionId,
+      set: { lastActivity: now },
+      setWhere: lt(activeSessions.lastActivity, heartbeatThreshold),
+    });
+
+  if (Math.random() < 0.05) {
+    const cleanupThreshold = new Date(Date.now() - SESSION_TIMEOUT_MS);
+    db.delete(activeSessions)
+      .where(lt(activeSessions.lastActivity, cleanupThreshold))
+      .catch(err => console.error('Cleanup error:', err));
+  }
+
+  const countThreshold = new Date(Date.now() - SESSION_TIMEOUT_MS);
+  const result = await db
+    .select({ total: sql<number>`count(*)` })
+    .from(activeSessions)
+    .where(gte(activeSessions.lastActivity, countThreshold));
+
+  return Number(result[0]?.total || 0);
+}
+
+
+export async function POST() {
+   try {
     const cookieStore = await cookies();
     let sessionId = cookieStore.get('user_session_id')?.value;
 
@@ -26,47 +80,10 @@ export async function POST() {
       sessionId = randomUUID();
     }
 
-    const now = new Date();
-    const heartbeatThreshold = new Date(
-      now.getTime() - getHeartbeatThrottleMs()
-    );
-
-    await db
-      .insert(activeSessions)
-      .values({
-        sessionId,
-        lastActivity: now,
-      })
-      .onConflictDoUpdate({
-        target: activeSessions.sessionId,
-        set: { lastActivity: now },
-        setWhere: lt(activeSessions.lastActivity, heartbeatThreshold),
-      });
-
-    if (Math.random() < 0.05) {
-      const cleanupThreshold = new Date(
-        Date.now() - SESSION_TIMEOUT_MINUTES * 60 * 1000
-      );
-
-      db.delete(activeSessions)
-        .where(lt(activeSessions.lastActivity, cleanupThreshold))
-        .catch(err => console.error('Cleanup error:', err));
-    }
-
-    const countThreshold = new Date(
-      Date.now() - SESSION_TIMEOUT_MINUTES * 60 * 1000
-    );
+    const redisCount = await heartbeatViaRedis(sessionId);
+    const online = redisCount ?? (await heartbeatViaDb(sessionId));
 
-    const result = await db
-      .select({
-        total: sql<number>`count(*)`,
-      })
-      .from(activeSessions)
-      .where(gte(activeSessions.lastActivity, countThreshold));
-
-    const response = NextResponse.json({
-      online: Number(result[0]?.total || 0),
-    });
+    const response = NextResponse.json({ online });
 
     response.cookies.set('user_session_id', sessionId, {
       httpOnly: true,
diff --git a/frontend/lib/about/stats.ts b/frontend/lib/about/stats.ts
index c4ee20ef..e51afc9d 100644
--- a/frontend/lib/about/stats.ts
+++ b/frontend/lib/about/stats.ts
@@ -43,7 +43,7 @@ export const getPlatformStats = unstable_cache(
 
     const linkedinCount = process.env.LINKEDIN_FOLLOWER_COUNT
       ? parseInt(process.env.LINKEDIN_FOLLOWER_COUNT)
-      : 1700;
+      : 1800;
 
     let totalUsers = 243;
     let solvedTests = 1890;