diff --git a/package-lock.json b/package-lock.json
index 1861541..18e9441 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -14,15 +14,18 @@
         "@prisma/client": "^5.14.0",
         "@radix-ui/react-alert-dialog": "^1.1.6",
         "@radix-ui/react-avatar": "^1.1.3",
+        "@radix-ui/react-checkbox": "^1.1.4",
         "@radix-ui/react-dialog": "^1.1.6",
         "@radix-ui/react-dropdown-menu": "^2.1.6",
         "@radix-ui/react-label": "^2.1.2",
         "@radix-ui/react-popover": "^1.1.6",
+        "@radix-ui/react-scroll-area": "^1.2.3",
         "@radix-ui/react-select": "^2.1.6",
         "@radix-ui/react-separator": "^1.1.2",
         "@radix-ui/react-slot": "^1.1.2",
         "@radix-ui/react-switch": "^1.1.3",
         "@radix-ui/react-tabs": "^1.1.3",
+        "@radix-ui/react-tooltip": "^1.1.8",
         "@t3-oss/env-nextjs": "^0.10.1",
         "@tanstack/react-query": "^5.50.0",
         "@trpc/client": "^11.0.0-rc.446",
@@ -19213,6 +19216,35 @@
         }
       }
     },
+    "node_modules/@radix-ui/react-checkbox": {
+      "version": "1.1.4",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-checkbox/-/react-checkbox-1.1.4.tgz",
+      "integrity": "sha512-wP0CPAHq+P5I4INKe3hJrIa1WoNqqrejzW+zoU0rOvo1b9gDEJJFl2rYfO1PYJUQCc2H1WZxIJmyv9BS8i5fLw==",
+      "dependencies": {
+        "@radix-ui/primitive": "1.1.1",
+        "@radix-ui/react-compose-refs": "1.1.1",
+        "@radix-ui/react-context": "1.1.1",
+        "@radix-ui/react-presence": "1.1.2",
+        "@radix-ui/react-primitive": "2.0.2",
+        "@radix-ui/react-use-controllable-state": "1.1.0",
+        "@radix-ui/react-use-previous": "1.1.0",
+        "@radix-ui/react-use-size": "1.1.0"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@radix-ui/react-collection": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/@radix-ui/react-collection/-/react-collection-1.1.2.tgz",
@@ -19668,6 +19700,36 @@
         }
       }
     },
+    "node_modules/@radix-ui/react-scroll-area": {
+      "version": "1.2.3",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-scroll-area/-/react-scroll-area-1.2.3.tgz",
+      "integrity": "sha512-l7+NNBfBYYJa9tNqVcP2AGvxdE3lmE6kFTBXdvHgUaZuy+4wGCL1Cl2AfaR7RKyimj7lZURGLwFO59k4eBnDJQ==",
+      "dependencies": {
+        "@radix-ui/number": "1.1.0",
+        "@radix-ui/primitive": "1.1.1",
+        "@radix-ui/react-compose-refs": "1.1.1",
+        "@radix-ui/react-context": "1.1.1",
+        "@radix-ui/react-direction": "1.1.0",
+        "@radix-ui/react-presence": "1.1.2",
+        "@radix-ui/react-primitive": "2.0.2",
+        "@radix-ui/react-use-callback-ref": "1.1.0",
+        "@radix-ui/react-use-layout-effect": "1.1.0"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@radix-ui/react-select": {
       "version": "2.1.6",
       "resolved": "https://registry.npmjs.org/@radix-ui/react-select/-/react-select-2.1.6.tgz",
@@ -19811,6 +19873,39 @@
         }
       }
     },
+    "node_modules/@radix-ui/react-tooltip": {
+      "version": "1.1.8",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-tooltip/-/react-tooltip-1.1.8.tgz",
+      "integrity": "sha512-YAA2cu48EkJZdAMHC0dqo9kialOcRStbtiY4nJPaht7Ptrhcvpo+eDChaM6BIs8kL6a8Z5l5poiqLnXcNduOkA==",
+      "dependencies": {
+        "@radix-ui/primitive": "1.1.1",
+        "@radix-ui/react-compose-refs": "1.1.1",
+        "@radix-ui/react-context": "1.1.1",
+        "@radix-ui/react-dismissable-layer": "1.1.5",
+        "@radix-ui/react-id": "1.1.0",
+        "@radix-ui/react-popper": "1.2.2",
+        "@radix-ui/react-portal": "1.1.4",
+        "@radix-ui/react-presence": "1.1.2",
+        "@radix-ui/react-primitive": "2.0.2",
+        "@radix-ui/react-slot": "1.1.2",
+        "@radix-ui/react-use-controllable-state": "1.1.0",
+        "@radix-ui/react-visually-hidden": "1.1.2"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@radix-ui/react-use-callback-ref": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/@radix-ui/react-use-callback-ref/-/react-use-callback-ref-1.1.0.tgz",
diff --git a/package.json b/package.json
index d1170af..eff8fdf 100644
--- a/package.json
+++ b/package.json
@@ -28,15 +28,18 @@
     "@prisma/client": "^5.14.0",
     "@radix-ui/react-alert-dialog": "^1.1.6",
     "@radix-ui/react-avatar": "^1.1.3",
+    "@radix-ui/react-checkbox": "^1.1.4",
     "@radix-ui/react-dialog": "^1.1.6",
     "@radix-ui/react-dropdown-menu": "^2.1.6",
     "@radix-ui/react-label": "^2.1.2",
     "@radix-ui/react-popover": "^1.1.6",
+    "@radix-ui/react-scroll-area": "^1.2.3",
     "@radix-ui/react-select": "^2.1.6",
     "@radix-ui/react-separator": "^1.1.2",
     "@radix-ui/react-slot": "^1.1.2",
     "@radix-ui/react-switch": "^1.1.3",
     "@radix-ui/react-tabs": "^1.1.3",
+    "@radix-ui/react-tooltip": "^1.1.8",
     "@t3-oss/env-nextjs": "^0.10.1",
     "@tanstack/react-query": "^5.50.0",
     "@trpc/client": "^11.0.0-rc.446",
diff --git a/prisma/migrations/20250323024640_store_user_activity_and_notifications/migration.sql b/prisma/migrations/20250323024640_store_user_activity_and_notifications/migration.sql
new file mode 100644
index 0000000..31763be
--- /dev/null
+++ b/prisma/migrations/20250323024640_store_user_activity_and_notifications/migration.sql
@@ -0,0 +1,44 @@
+-- CreateEnum
+CREATE TYPE "ActivityType" AS ENUM ('TASK_CREATED', 'TASK_UPDATED', 'TASK_DELETED', 'TASK_STATUS_CHANGED', 'TASK_ASSIGNED', 'TASK_TAGGED', 'PROJECT_CREATED', 'PROJECT_UPDATED', 'PROJECT_DELETED', 'MEMBER_ADDED', 'MEMBER_REMOVED', 'MEMBER_ROLE_CHANGED');
+
+-- CreateEnum
+CREATE TYPE "NotificationType" AS ENUM ('TASK_ASSIGNED', 'TASK_TAGGED', 'INVITATION_RECEIVED', 'INVITATION_ACCEPTED', 'TASK_DUE_SOON');
+
+-- CreateTable
+CREATE TABLE "Activity" (
+    "id" TEXT NOT NULL,
+    "type" "ActivityType" NOT NULL,
+    "description" TEXT NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "userId" TEXT NOT NULL,
+    "projectId" TEXT NOT NULL,
+    "taskId" TEXT,
+    "metadata" JSONB,
+
+    CONSTRAINT "Activity_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateTable
+CREATE TABLE "Notification" (
+    "id" TEXT NOT NULL,
+    "type" "NotificationType" NOT NULL,
+    "message" TEXT NOT NULL,
+    "isRead" BOOLEAN NOT NULL DEFAULT false,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "userId" TEXT NOT NULL,
+    "metadata" JSONB,
+
+    CONSTRAINT "Notification_pkey" PRIMARY KEY ("id")
+);
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_projectId_fkey" FOREIGN KEY ("projectId") REFERENCES "Project"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_taskId_fkey" FOREIGN KEY ("taskId") REFERENCES "Task"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "Notification" ADD CONSTRAINT "Notification_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User"("id") ON DELETE CASCADE ON UPDATE CASCADE;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 4582e7e..5a000a5 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -1,8 +1,7 @@
-
 generator client {
-    provider = "prisma-client-js"
+    provider        = "prisma-client-js"
     previewFeatures = ["jsonProtocol"]
-    binaryTargets = ["native", "linux-arm64-openssl-1.0.x"]
+    binaryTargets   = ["native", "linux-arm64-openssl-1.0.x"]
 }
 
 datasource db {
@@ -47,7 +46,7 @@ model User {
     image         String?
     preferences   Json?
     createdAt     DateTime  @default(now())
-    updatedAt     DateTime?  @updatedAt
+    updatedAt     DateTime? @updatedAt
 
     // Relationships
     createdProjects Project[]       @relation("ProjectOwner")
@@ -56,6 +55,8 @@ model User {
     assignedTasks   Task[]          @relation("AssignedTasks")
     taggedTasks     TaskTag[]
     invitations     Invitation[]    @relation("InvitedBy")
+    activities      Activity[]
+    notifications   Notification[]
 
     // NextAuth relations
     accounts Account[]
@@ -75,6 +76,7 @@ model Project {
     members     ProjectMember[]
     tasks       Task[]
     invitations Invitation[]
+    activities  Activity[]
 }
 
 enum UserRoles {
@@ -142,12 +144,13 @@ model Task {
 
     // Relationships
     projectId    String
-    project      Project   @relation(fields: [projectId], references: [id], onDelete: Cascade)
+    project      Project    @relation(fields: [projectId], references: [id], onDelete: Cascade)
     createdById  String
-    createdBy    User      @relation(fields: [createdById], references: [id])
+    createdBy    User       @relation(fields: [createdById], references: [id])
     assignedToId String?
-    assignedTo   User?     @relation("AssignedTasks", fields: [assignedToId], references: [id])
+    assignedTo   User?      @relation("AssignedTasks", fields: [assignedToId], references: [id])
     tags         TaskTag[]
+    activities   Activity[]
 }
 
 model TaskTag {
@@ -160,3 +163,53 @@ model TaskTag {
 
     @@unique([taskId, userId])
 }
+
+enum ActivityType {
+    TASK_CREATED
+    TASK_UPDATED
+    TASK_DELETED
+    TASK_STATUS_CHANGED
+    TASK_ASSIGNED
+    TASK_TAGGED
+    PROJECT_CREATED
+    PROJECT_UPDATED
+    PROJECT_DELETED
+    MEMBER_ADDED
+    MEMBER_REMOVED
+    MEMBER_ROLE_CHANGED
+}
+
+model Activity {
+    id          String       @id @default(cuid())
+    type        ActivityType
+    description String
+    createdAt   DateTime     @default(now())
+    userId      String
+    projectId   String
+    taskId      String?
+    metadata    Json?
+
+    user    User    @relation(fields: [userId], references: [id], onDelete: Cascade)
+    project Project @relation(fields: [projectId], references: [id], onDelete: Cascade)
+    task    Task?   @relation(fields: [taskId], references: [id], onDelete: Cascade)
+}
+
+enum NotificationType {
+    TASK_ASSIGNED
+    TASK_TAGGED
+    INVITATION_RECEIVED
+    INVITATION_ACCEPTED
+    TASK_DUE_SOON
+}
+
+model Notification {
+    id        String           @id @default(cuid())
+    type      NotificationType
+    message   String
+    isRead    Boolean          @default(false)
+    createdAt DateTime         @default(now())
+    userId    String
+    metadata  Json?
+
+    user User @relation(fields: [userId], references: [id], onDelete: Cascade)
+}
diff --git a/src/app/dashboard/layout.tsx b/src/app/dashboard/layout.tsx
index 48ec779..e5a7840 100644
--- a/src/app/dashboard/layout.tsx
+++ b/src/app/dashboard/layout.tsx
@@ -36,7 +36,7 @@ export default async function DashboardLayout({ children }: { children: React.Re
                 </div>
             </header>
             <div className="flex-1 items-start md:grid md:grid-cols-[220px_1fr] md:gap-6 lg:grid-cols-[240px_1fr]">
-                <aside className="fixed top-14 z-30 -ml-2 hidden h-full w-full shrink-0 overflow-y-auto border-r md:sticky md:block">
+                <aside className="fixed top-20 z-30 -ml-2 hidden h-[85vh] w-full shrink-0 overflow-y-auto border-r md:sticky md:block">
                     <DashboardNav />
                 </aside>
                 <main className="flex w-full flex-col overflow-hidden px-4 md:pr-8 md:py-8">{children}</main>
diff --git a/src/app/dashboard/projects/[projectId]/settings/page.tsx b/src/app/dashboard/projects/[projectId]/settings/page.tsx
index 4d194fe..e8bd287 100644
--- a/src/app/dashboard/projects/[projectId]/settings/page.tsx
+++ b/src/app/dashboard/projects/[projectId]/settings/page.tsx
@@ -64,7 +64,7 @@ export default function ProjectSettingsPage({ params }: ProjectSettingsPageProps
                     return;
                 }
                 setProjectId(projectId);
-            } catch(e) {
+            } catch (e) {
                 console.log(e);
             }
         }
@@ -77,7 +77,10 @@ export default function ProjectSettingsPage({ params }: ProjectSettingsPageProps
     // Fetch project details
     const { data: project, isLoading: isProjectLoading } = api.project.getById.useQuery({
         projectId: projectId,
-    });
+    }, {
+        enabled: !!projectId,
+    }
+    );
 
     // Check if user is the owner
     const { data: session } = api.user.getSession.useQuery();
diff --git a/src/components/dashboard/ProjectCard.tsx b/src/components/dashboard/ProjectCard.tsx
index bd99ec4..dcfa0ea 100644
--- a/src/components/dashboard/ProjectCard.tsx
+++ b/src/components/dashboard/ProjectCard.tsx
@@ -28,7 +28,7 @@ export function ProjectCard({ project, taskCount, memberCount }: ProjectCardProp
                             <Link href={`/dashboard/projects/${project.id}`}>View Project</Link>
                         </DropdownMenuItem>
                         <DropdownMenuItem asChild>
-                            <Link href={`/dashboard/projects/${project.id}/edit`}>Edit Project</Link>
+                            <Link href={`/dashboard/projects/${project.id}/settings`}>Edit Project</Link>
                         </DropdownMenuItem>
                     </DropdownMenuContent>
                 </DropdownMenu>
diff --git a/src/components/dashboard/UserDropdown.tsx b/src/components/dashboard/UserDropdown.tsx
index 08597bd..bf0d682 100644
--- a/src/components/dashboard/UserDropdown.tsx
+++ b/src/components/dashboard/UserDropdown.tsx
@@ -12,6 +12,7 @@ import {
 } from "@/components/ui/dropdown-menu";
 import { Button } from "@/components/ui/button";
 import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
+import { NotificationDropdown } from "../notifications/NotificationDropdown";
 
 
 interface UserNavProps {
@@ -20,40 +21,43 @@ interface UserNavProps {
 
 export function UserDropdown({ user }: UserNavProps) {
     return (
-        <DropdownMenu>
-            <DropdownMenuTrigger asChild>
-                <Button variant="ghost" className="relative h-8 w-8 rounded-full">
-                    <Avatar className="h-8 w-8">
-                        <AvatarImage src={user.image ?? ""} alt={user.name ?? "User"} />
-                        <AvatarFallback>{user.name?.charAt(0) ?? "U"}</AvatarFallback>
-                    </Avatar>
-                </Button>
-            </DropdownMenuTrigger>
-            <DropdownMenuContent className="w-56" align="end" forceMount>
-                <DropdownMenuLabel className="font-normal">
-                    <div className="flex flex-col space-y-1">
-                        <p className="text-sm font-medium leading-none">{user.name}</p>
-                        <p className="text-xs leading-none text-muted-foreground">{user.email}</p>
-                    </div>
-                </DropdownMenuLabel>
-                <DropdownMenuSeparator />
-                <DropdownMenuItem asChild>
-                    <Link href="/dashboard/settings">Profile</Link>
-                </DropdownMenuItem>
-                <DropdownMenuItem asChild>
-                    <Link href="/dashboard/settings">Settings</Link>
-                </DropdownMenuItem>
-                <DropdownMenuSeparator />
-                <DropdownMenuItem
-                    className="cursor-pointer"
-                    onSelect={(event) => {
-                        event.preventDefault()
-                        void signOut();
-                    }}
-                >
-                    Sign out
-                </DropdownMenuItem>
-            </DropdownMenuContent>
-        </DropdownMenu>
+        <div className="flex items-center gap-2">
+            <NotificationDropdown />
+            <DropdownMenu>
+                <DropdownMenuTrigger asChild>
+                    <Button variant="ghost" className="relative h-8 w-8 rounded-full">
+                        <Avatar className="h-8 w-8">
+                            <AvatarImage src={user.image ?? ""} alt={user.name ?? "User"} />
+                            <AvatarFallback>{user.name?.charAt(0) ?? "U"}</AvatarFallback>
+                        </Avatar>
+                    </Button>
+                </DropdownMenuTrigger>
+                <DropdownMenuContent className="w-56" align="end" forceMount>
+                    <DropdownMenuLabel className="font-normal">
+                        <div className="flex flex-col space-y-1">
+                            <p className="text-sm font-medium leading-none">{user.name}</p>
+                            <p className="text-xs leading-none text-muted-foreground">{user.email}</p>
+                        </div>
+                    </DropdownMenuLabel>
+                    <DropdownMenuSeparator />
+                    <DropdownMenuItem asChild>
+                        <Link href="/dashboard/settings">Profile</Link>
+                    </DropdownMenuItem>
+                    <DropdownMenuItem asChild>
+                        <Link href="/dashboard/settings">Settings</Link>
+                    </DropdownMenuItem>
+                    <DropdownMenuSeparator />
+                    <DropdownMenuItem
+                        className="cursor-pointer"
+                        onSelect={(event) => {
+                            event.preventDefault()
+                            void signOut();
+                        }}
+                    >
+                        Sign out
+                    </DropdownMenuItem>
+                </DropdownMenuContent>
+            </DropdownMenu>
+        </div>
     )
 }
\ No newline at end of file
diff --git a/src/components/notifications/NotificationDropdown.tsx b/src/components/notifications/NotificationDropdown.tsx
new file mode 100644
index 0000000..7d4c202
--- /dev/null
+++ b/src/components/notifications/NotificationDropdown.tsx
@@ -0,0 +1,100 @@
+"use client"
+
+import { useState } from "react";
+import { Bell } from "lucide-react";
+import { formatDistanceToNow } from "date-fns";
+import { Button } from "@/components/ui/button";
+import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "@/components/ui/dropdown-menu";
+import { api } from "@/trpc/react";
+import { Badge } from "@/components/ui/badge";
+import { Separator } from "@/components/ui/separator";
+import { toast } from "sonner";
+import { getNotificationIcon } from "@/lib/constants";
+
+export function NotificationDropdown() {
+    const [isOpen, setIsOpen] = useState(false);
+
+    const { data: notifications, refetch: refetchNotifications } = api.notification.getMyNotifications.useQuery();
+    const { data: unreadCount, refetch: refetchUnreadCount } = api.notification.getUnreadCount.useQuery();
+
+    // method to mark one notification as read -> will take notificationId as argument
+    const markAsRead = api.notification.markAsRead.useMutation({
+        onSuccess: async () => {
+            await refetchNotifications();
+            await refetchUnreadCount();
+        },
+    });
+
+    // method to mark all notifications as read
+    const markAllAsRead = api.notification.markAllAsRead.useMutation({
+        onSuccess: async () => {
+            toast.success("Notifications marked as read", {
+                description: "All notifications have been marked as read",
+            });
+            await refetchNotifications();
+            await refetchUnreadCount();
+            setIsOpen(false);
+        },
+    });
+
+    const handleMarkAsRead = (notificationId: string) => {
+        markAsRead.mutate({ notificationId });
+    }
+
+    const handleMarkAllAsRead = () => {
+        markAllAsRead.mutate();
+    }
+
+
+    return (
+        <DropdownMenu open={isOpen} onOpenChange={setIsOpen}>
+            <DropdownMenuTrigger asChild className="mt-1 mr-1">
+                <Button variant="ghost" size="icon" className="relative">
+                    <Bell className="h-5 w-5" />
+                    {unreadCount && unreadCount > 0 && (
+                        <Badge
+                            variant="destructive"
+                            className="absolute -right-1 -top-0.5 h-4 w-4 rounded-full p-0 flex items-center justify-center text-xs"
+                        >
+                            {unreadCount > 9 ? "9+" : unreadCount}
+                        </Badge>
+                    )}
+                </Button>
+            </DropdownMenuTrigger>
+            <DropdownMenuContent align="end" className="w-80">
+                <div className="flex items-center justify-between p-4">
+                    <h3 className="font-medium">Notifications</h3>
+                    {unreadCount && unreadCount > 0 && (
+                        <Button variant="ghost" size="sm" onClick={handleMarkAllAsRead} className="text-xs">
+                            Mark all as read
+                        </Button>
+                    )}
+                </div>
+                <Separator />
+                <div className="max-h-96 overflow-y-auto">
+                    {notifications && notifications.length > 0 ? (
+                        notifications.map((notification) => (
+                            <DropdownMenuItem
+                                key={notification.id}
+                                className={`flex flex-col items-start p-4 ${!notification.isRead ? "bg-muted/50" : ""}`}
+                                onClick={() => handleMarkAsRead(notification.id)}
+                            >
+                                <div className="flex w-full">
+                                    <span className="mr-2 text-lg">{getNotificationIcon(notification.type)}</span>
+                                    <div className="flex-1">
+                                        <p className="text-sm">{notification.message}</p>
+                                        <p className="text-xs text-muted-foreground">
+                                            {formatDistanceToNow(new Date(notification.createdAt), { addSuffix: true })}
+                                        </p>
+                                    </div>
+                                </div>
+                            </DropdownMenuItem>
+                        ))
+                    ) : (
+                        <div className="p-4 text-center text-sm text-muted-foreground">No notifications</div>
+                    )}
+                </div>
+            </DropdownMenuContent>
+        </DropdownMenu>
+    )
+}
diff --git a/src/components/project/TaskActivityFeed.tsx b/src/components/project/TaskActivityFeed.tsx
new file mode 100644
index 0000000..303286b
--- /dev/null
+++ b/src/components/project/TaskActivityFeed.tsx
@@ -0,0 +1,58 @@
+"use client";
+import { api } from "@/trpc/react";
+import { formatDistanceToNow } from "date-fns";
+import { Activity } from "lucide-react";
+import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
+import { getActivityIcon } from "@/lib/constants";
+
+
+interface TaskActivityFeedProps {
+    taskId: string
+}
+
+export function TaskActivityFeed({ taskId }: TaskActivityFeedProps) {
+    const { data: activities, isLoading } = api.task.getTaskActivities.useQuery({ taskId });
+
+    if (isLoading) {
+        return (
+            <div className="flex items-center justify-center p-4">
+                <div className="h-6 w-6 animate-spin rounded-full border-2 border-primary border-t-transparent"></div>
+            </div>
+        )
+    }
+
+    if (!activities || activities.length === 0) {
+        return (
+            <div className="flex flex-col items-center justify-center p-8 text-center">
+                <Activity className="h-10 w-10 text-muted-foreground" />
+                <p className="mt-2 text-sm text-muted-foreground">No activity recorded yet</p>
+            </div>
+        )
+    }
+
+    return (
+        <div className="space-y-4">
+            <h3 className="text-lg font-medium">Activity Feed</h3>
+            <div className="space-y-4">
+                {activities.map((activity) => (
+                    <div key={activity.id} className="flex items-start space-x-3">
+                        <div className="flex-shrink-0 text-lg">{getActivityIcon(activity.type)}</div>
+                        <div className="flex-1 space-y-1">
+                            <div className="flex items-center">
+                                <Avatar className="h-6 w-6 mr-2">
+                                    <AvatarImage src={activity.user.image ?? ""} alt={activity.user.name ?? "User"} />
+                                    <AvatarFallback>{activity.user.name?.charAt(0) ?? "U"}</AvatarFallback>
+                                </Avatar>
+                                <span className="text-sm font-medium">{activity.user.name}</span>
+                            </div>
+                            <p className="text-sm">{activity.description}</p>
+                            <p className="text-xs text-muted-foreground">
+                                {formatDistanceToNow(new Date(activity.createdAt), { addSuffix: true })}
+                            </p>
+                        </div>
+                    </div>
+                ))}
+            </div>
+        </div>
+    )
+}
diff --git a/src/components/project/TaskCard.tsx b/src/components/project/TaskCard.tsx
index 6e91212..ebc5e7d 100644
--- a/src/components/project/TaskCard.tsx
+++ b/src/components/project/TaskCard.tsx
@@ -21,11 +21,15 @@ import {
 } from "@/components/ui/alert-dialog";
 import { toast } from "sonner";
 import { type TaskCardProps } from "@/lib/types";
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from "@/components/ui/tooltip";
+import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
+import { TaskActivityFeed } from "./TaskActivityFeed";
 
 
 export function TaskCard({ task, projectId, members, isAdmin, onDelete, onUpdate }: TaskCardProps) {
-    const [isEditDialogOpen, setIsEditDialogOpen] = useState(false);
-    const [isDeleteDialogOpen, setIsDeleteDialogOpen] = useState(false);
+    const [isEditDialogOpen, setIsEditDialogOpen] = useState<boolean>(false);
+    const [isDeleteDialogOpen, setIsDeleteDialogOpen] = useState<boolean>(false);
+    const [isActivityOpen, setIsActivityOpen] = useState<boolean>(false);
 
     // method to delete a task
     const deleteTask = api.task.delete.useMutation({
@@ -81,6 +85,7 @@ export function TaskCard({ task, projectId, members, isAdmin, onDelete, onUpdate
                                 </Button>
                             </DropdownMenuTrigger>
                             <DropdownMenuContent align="end">
+                                <DropdownMenuItem onClick={() => setIsActivityOpen(true)}>View Activity</DropdownMenuItem>
                                 <DropdownMenuItem onClick={() => setIsEditDialogOpen(true)}>Edit Task</DropdownMenuItem>
                                 {canEdit && (
                                     <DropdownMenuItem
@@ -94,6 +99,7 @@ export function TaskCard({ task, projectId, members, isAdmin, onDelete, onUpdate
                         </DropdownMenu>
                     </div>
                 </CardHeader>
+
                 <CardContent className="p-3">
                     <div className="flex flex-wrap gap-2 mb-2">
                         <Badge variant="outline" className={getPriorityColor(task.priority)}>
@@ -107,17 +113,55 @@ export function TaskCard({ task, projectId, members, isAdmin, onDelete, onUpdate
                     )}
                     <p className="text-sm text-muted-foreground line-clamp-2">{task.description ?? "No description provided."}</p>
                 </CardContent>
-                <CardFooter className="p-3 pt-0 flex justify-between text-xs text-muted-foreground">
-                    <div className="flex items-center">
-                        <Calendar className="mr-1 h-3.5 w-3.5" />
-                        <span>{formatDistanceToNow(new Date(task.deadline), { addSuffix: true })}</span>
-                    </div>
-                    {task?.assignedTo && (
+
+                <CardFooter className="flex flex-col-reverse p-0 mb-2 gap-2">
+
+                    <div className="p-2 pt-0 flex justify-between text-xs text-muted-foreground w-full">
                         <div className="flex items-center">
-                            <User2 className="mr-1 h-3.5 w-3.5" />
-                            <span>{task.assignedTo.name}</span>
+                            <Calendar className="mr-1 h-3.5 w-3.5" />
+                            <span>{formatDistanceToNow(new Date(task.deadline), { addSuffix: true })}</span>
                         </div>
-                    )}
+                        {task?.assignedTo && (
+                            <div className="flex items-center">
+                                <User2 className="mr-1 h-3.5 w-3.5" />
+                                <span>{task.assignedTo.name}</span>
+                            </div>
+                        )}
+                    </div>
+
+                    <div className="flex justify-end items-center gap-1 w-full px-2">
+                        {task.tags && task.tags.length > 0 && task.tags.slice(0, 3).map((tag) => (
+                            <TooltipProvider key={tag.id}>
+                                <Tooltip>
+                                    <TooltipTrigger asChild>
+                                        <Avatar className="h-5 w-5">
+                                            <AvatarImage src={tag.user.image ?? ""} alt={tag.user.name ?? "User"} />
+                                            <AvatarFallback className="text-[10px]">{tag.user.name?.charAt(0) ?? "U"}</AvatarFallback>
+                                        </Avatar>
+                                    </TooltipTrigger>
+                                    <TooltipContent>
+                                        <p>Tagged: {tag.user.name}</p>
+                                    </TooltipContent>
+                                </Tooltip>
+                            </TooltipProvider>
+                        ))}
+
+                        {task.tags && task.tags.length > 3 && (
+                            <TooltipProvider>
+                                <Tooltip>
+                                    <TooltipTrigger asChild>
+                                        <Badge variant="outline" className="h-5 w-5 p-0 flex items-center justify-center rounded-full">
+                                            +{task.tags.length - 3}
+                                        </Badge>
+                                    </TooltipTrigger>
+                                    <TooltipContent>
+                                        <p>{task.tags.length - 3} more tagged users</p>
+                                    </TooltipContent>
+                                </Tooltip>
+                            </TooltipProvider>
+                        )}
+                    </div>
+
                 </CardFooter>
             </Card>
 
@@ -147,6 +191,21 @@ export function TaskCard({ task, projectId, members, isAdmin, onDelete, onUpdate
                     </AlertDialogFooter>
                 </AlertDialogContent>
             </AlertDialog>
+
+            <AlertDialog open={isActivityOpen} onOpenChange={setIsActivityOpen}>
+                <AlertDialogContent className="max-w-3xl">
+                    <AlertDialogHeader>
+                        <AlertDialogTitle>Task Activity</AlertDialogTitle>
+                        <AlertDialogDescription>View the activity history for this task.</AlertDialogDescription>
+                    </AlertDialogHeader>
+                    <div className="max-h-[60vh] overflow-y-auto">
+                        <TaskActivityFeed taskId={task.id} />
+                    </div>
+                    <AlertDialogFooter>
+                        <AlertDialogCancel>Close</AlertDialogCancel>
+                    </AlertDialogFooter>
+                </AlertDialogContent>
+            </AlertDialog>
         </>
     )
 }
\ No newline at end of file
diff --git a/src/components/project/dialog/EditTaskDialog.tsx b/src/components/project/dialog/EditTaskDialog.tsx
index c24f50e..3d5f5f4 100644
--- a/src/components/project/dialog/EditTaskDialog.tsx
+++ b/src/components/project/dialog/EditTaskDialog.tsx
@@ -25,6 +25,9 @@ import { cn } from "@/lib/utils";
 import { api } from "@/trpc/react";
 import { toast } from "sonner";
 import { type EditTaskDialogProps } from "@/lib/types";
+import { ScrollArea } from "@/components/ui/scroll-area";
+import { Checkbox } from "@/components/ui/checkbox";
+import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
 
 
 const taskFormSchema = z.object({
@@ -49,6 +52,7 @@ const taskFormSchema = z.object({
         required_error: "Please select a deadline date.",
     }),
     assignedToId: z.string().optional(),
+    taggedUserIds: z.array(z.string()).optional(),
 });
 
 type TaskFormValues = z.infer<typeof taskFormSchema>;
@@ -62,8 +66,9 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
             toast.success("Task updated", {
                 description: "Your task has been updated successfully.",
             });
-            onUpdate(data);
+            if (data) onUpdate(data);
             onOpenChange(false);
+            setIsLoading(false);
         },
         onError: (error) => {
             toast.error("Error", {
@@ -73,6 +78,9 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
         },
     });
 
+    // get current tagged users
+    const currentTaggedUserIds = task?.tags ? task.tags.map((tag) => tag?.userId) : [];
+
     // edit task form state
     const form = useForm<TaskFormValues>({
         resolver: zodResolver(taskFormSchema),
@@ -83,6 +91,7 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
             status: task.status,
             deadline: new Date(task.deadline),
             assignedToId: task.assignedToId ?? "",
+            taggedUserIds: currentTaggedUserIds,
         },
     });
 
@@ -96,6 +105,7 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
                 status: task.status,
                 deadline: new Date(task.deadline),
                 assignedToId: task.assignedToId ?? "",
+                taggedUserIds: currentTaggedUserIds,
             })
         }
     }, [task, form, open]);
@@ -111,13 +121,14 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
             status: data.status,
             deadline: data.deadline,
             assignedToId: data.assignedToId === "unassigned" ? undefined : data.assignedToId,
+            taggedUserIds: data.taggedUserIds ?? [],
         });
     }
-    
+
 
     return (
         <Dialog open={open} onOpenChange={onOpenChange}>
-            <DialogContent className="sm:max-w-[600px]">
+            <DialogContent className="sm:max-w-[600px] h-4/5 overflow-y-auto">
                 <DialogHeader>
                     <DialogTitle>Edit Task</DialogTitle>
                     <DialogDescription>Update the task details below.</DialogDescription>
@@ -257,6 +268,52 @@ export function EditTaskDialog({ open, onOpenChange, task, members, onUpdate }:
                                 )}
                             />
                         </div>
+                        <FormField
+                            control={form.control}
+                            name="taggedUserIds"
+                            render={() => (
+                                <FormItem>
+                                    <FormLabel>Tag Team Members</FormLabel>
+                                    <ScrollArea className="h-[200px] border rounded-md p-4">
+                                        <div className="space-y-4">
+                                            {members.filter(member => member.userId !== task.createdById && member.userId !== task.assignedToId).map((member) => (
+                                                <FormField
+                                                    key={member.id}
+                                                    control={form.control}
+                                                    name="taggedUserIds"
+                                                    render={({ field }) => {
+                                                        return (
+                                                            <FormItem key={member.userId} className="flex flex-row items-start space-x-3 space-y-0">
+                                                                <FormControl>
+                                                                    <Checkbox
+                                                                        checked={field.value?.includes(member.userId)}
+                                                                        onCheckedChange={(checked) => {
+                                                                            const currentValue = field.value ?? []
+                                                                            return checked
+                                                                                ? field.onChange([...currentValue, member.userId])
+                                                                                : field.onChange(currentValue.filter((value) => value !== member.userId))
+                                                                        }}
+                                                                    />
+                                                                </FormControl>
+                                                                <div className="flex items-center space-x-2">
+                                                                    <Avatar className="h-6 w-6">
+                                                                        <AvatarImage src={member.user.image ?? ""} alt={member.user.name ?? "User"} />
+                                                                        <AvatarFallback>{member.user.name?.charAt(0) ?? "U"}</AvatarFallback>
+                                                                    </Avatar>
+                                                                    <FormLabel className="font-normal cursor-pointer">{member.user.name}</FormLabel>
+                                                                </div>
+                                                            </FormItem>
+                                                        )
+                                                    }}
+                                                />
+                                            ))}
+                                        </div>
+                                    </ScrollArea>
+                                    <FormDescription>Tagged members will be notified and can view the task.</FormDescription>
+                                    <FormMessage />
+                                </FormItem>
+                            )}
+                        />
                         <DialogFooter>
                             <Button type="submit" disabled={isLoading}>
                                 {isLoading ? "Updating..." : "Update Task"}
diff --git a/src/components/ui/checkbox.tsx b/src/components/ui/checkbox.tsx
new file mode 100644
index 0000000..c6fdd07
--- /dev/null
+++ b/src/components/ui/checkbox.tsx
@@ -0,0 +1,30 @@
+"use client"
+
+import * as React from "react"
+import * as CheckboxPrimitive from "@radix-ui/react-checkbox"
+import { Check } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+const Checkbox = React.forwardRef<
+  React.ElementRef<typeof CheckboxPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof CheckboxPrimitive.Root>
+>(({ className, ...props }, ref) => (
+  <CheckboxPrimitive.Root
+    ref={ref}
+    className={cn(
+      "peer h-4 w-4 shrink-0 rounded-sm border border-primary shadow focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring disabled:cursor-not-allowed disabled:opacity-50 data-[state=checked]:bg-primary data-[state=checked]:text-primary-foreground",
+      className
+    )}
+    {...props}
+  >
+    <CheckboxPrimitive.Indicator
+      className={cn("flex items-center justify-center text-current")}
+    >
+      <Check className="h-4 w-4" />
+    </CheckboxPrimitive.Indicator>
+  </CheckboxPrimitive.Root>
+))
+Checkbox.displayName = CheckboxPrimitive.Root.displayName
+
+export { Checkbox }
diff --git a/src/components/ui/scroll-area.tsx b/src/components/ui/scroll-area.tsx
new file mode 100644
index 0000000..0b4a48d
--- /dev/null
+++ b/src/components/ui/scroll-area.tsx
@@ -0,0 +1,48 @@
+"use client"
+
+import * as React from "react"
+import * as ScrollAreaPrimitive from "@radix-ui/react-scroll-area"
+
+import { cn } from "@/lib/utils"
+
+const ScrollArea = React.forwardRef<
+  React.ElementRef<typeof ScrollAreaPrimitive.Root>,
+  React.ComponentPropsWithoutRef<typeof ScrollAreaPrimitive.Root>
+>(({ className, children, ...props }, ref) => (
+  <ScrollAreaPrimitive.Root
+    ref={ref}
+    className={cn("relative overflow-hidden", className)}
+    {...props}
+  >
+    <ScrollAreaPrimitive.Viewport className="h-full w-full rounded-[inherit]">
+      {children}
+    </ScrollAreaPrimitive.Viewport>
+    <ScrollBar />
+    <ScrollAreaPrimitive.Corner />
+  </ScrollAreaPrimitive.Root>
+))
+ScrollArea.displayName = ScrollAreaPrimitive.Root.displayName
+
+const ScrollBar = React.forwardRef<
+  React.ElementRef<typeof ScrollAreaPrimitive.ScrollAreaScrollbar>,
+  React.ComponentPropsWithoutRef<typeof ScrollAreaPrimitive.ScrollAreaScrollbar>
+>(({ className, orientation = "vertical", ...props }, ref) => (
+  <ScrollAreaPrimitive.ScrollAreaScrollbar
+    ref={ref}
+    orientation={orientation}
+    className={cn(
+      "flex touch-none select-none transition-colors",
+      orientation === "vertical" &&
+        "h-full w-2.5 border-l border-l-transparent p-[1px]",
+      orientation === "horizontal" &&
+        "h-2.5 flex-col border-t border-t-transparent p-[1px]",
+      className
+    )}
+    {...props}
+  >
+    <ScrollAreaPrimitive.ScrollAreaThumb className="relative flex-1 rounded-full bg-border" />
+  </ScrollAreaPrimitive.ScrollAreaScrollbar>
+))
+ScrollBar.displayName = ScrollAreaPrimitive.ScrollAreaScrollbar.displayName
+
+export { ScrollArea, ScrollBar }
diff --git a/src/components/ui/tooltip.tsx b/src/components/ui/tooltip.tsx
new file mode 100644
index 0000000..28e1918
--- /dev/null
+++ b/src/components/ui/tooltip.tsx
@@ -0,0 +1,32 @@
+"use client"
+
+import * as React from "react"
+import * as TooltipPrimitive from "@radix-ui/react-tooltip"
+
+import { cn } from "@/lib/utils"
+
+const TooltipProvider = TooltipPrimitive.Provider
+
+const Tooltip = TooltipPrimitive.Root
+
+const TooltipTrigger = TooltipPrimitive.Trigger
+
+const TooltipContent = React.forwardRef<
+  React.ElementRef<typeof TooltipPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof TooltipPrimitive.Content>
+>(({ className, sideOffset = 4, ...props }, ref) => (
+  <TooltipPrimitive.Portal>
+    <TooltipPrimitive.Content
+      ref={ref}
+      sideOffset={sideOffset}
+      className={cn(
+        "z-50 overflow-hidden rounded-md bg-primary px-3 py-1.5 text-xs text-primary-foreground animate-in fade-in-0 zoom-in-95 data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=closed]:zoom-out-95 data-[side=bottom]:slide-in-from-top-2 data-[side=left]:slide-in-from-right-2 data-[side=right]:slide-in-from-left-2 data-[side=top]:slide-in-from-bottom-2 origin-[--radix-tooltip-content-transform-origin]",
+        className
+      )}
+      {...props}
+    />
+  </TooltipPrimitive.Portal>
+))
+TooltipContent.displayName = TooltipPrimitive.Content.displayName
+
+export { Tooltip, TooltipTrigger, TooltipContent, TooltipProvider }
diff --git a/src/lib/constants.ts b/src/lib/constants.ts
index ed97638..312b314 100644
--- a/src/lib/constants.ts
+++ b/src/lib/constants.ts
@@ -90,4 +90,58 @@ export const statuses: { id: ProjectStatus; name: string }[] = [
     { id: "TODO", name: "To Do" },
     { id: "IN_PROGRESS", name: "In Progress" },
     { id: "DONE", name: "Done" },
-];
\ No newline at end of file
+];
+
+// helper function to pick css based on task priority
+export const getPriorityColor = (priority: string) => {
+    switch (priority) {
+        case "LOW":
+            return "bg-green-100 text-green-800 dark:bg-green-900 dark:text-green-300"
+        case "MEDIUM":
+            return "bg-blue-100 text-blue-800 dark:bg-blue-900 dark:text-blue-300"
+        case "HIGH":
+            return "bg-amber-100 text-amber-800 dark:bg-amber-900 dark:text-amber-300"
+        case "URGENT":
+            return "bg-red-100 text-red-800 dark:bg-red-900 dark:text-red-300"
+        default:
+            return "bg-gray-100 text-gray-800 dark:bg-gray-800 dark:text-gray-300"
+    }
+}
+
+// helper function to get activity type icon based on type
+export const getActivityIcon = (type: string) => {
+    switch (type) {
+        case "TASK_CREATED":
+            return "🆕"
+        case "TASK_UPDATED":
+            return "✏️"
+        case "TASK_DELETED":
+            return "🗑️"
+        case "TASK_STATUS_CHANGED":
+            return "🔄"
+        case "TASK_ASSIGNED":
+            return "👤"
+        case "TASK_TAGGED":
+            return "🏷️"
+        default:
+            return "📝"
+    }
+}
+
+// helper function to get notification type icon based on type
+export const getNotificationIcon = (type: string) => {
+    switch (type) {
+        case "TASK_ASSIGNED":
+            return "🎯"
+        case "TASK_TAGGED":
+            return "🏷️"
+        case "INVITATION_RECEIVED":
+            return "✉️"
+        case "INVITATION_ACCEPTED":
+            return "✅"
+        case "TASK_DUE_SOON":
+            return "⏰"
+        default:
+            return "📢"
+    }
+}
diff --git a/src/lib/types.ts b/src/lib/types.ts
index fef58a0..21ccba5 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -1,4 +1,4 @@
-import { type Task, type ProjectMember, type User, type Invitation, type Project } from "@prisma/client"
+import { type Task, type ProjectMember, type User, type Invitation, type Project, type TaskTag } from "@prisma/client"
 
 export interface ProjectPageProps {
     params: Promise<{ projectId: string }>;
@@ -8,9 +8,14 @@ interface Members extends ProjectMember {
     user: User
 }
 
+interface TaskTagWithUser extends TaskTag {
+    user: User
+}
+
 interface TaskWithUser extends Task {
     assignedTo?: User | null;
     createdBy?: User | null;
+    tags?: TaskTagWithUser[] | null;
 }
 
 export interface TaskBoardProps {
@@ -31,7 +36,7 @@ export interface AddTaskDialogProps {
 export interface EditTaskDialogProps {
     open: boolean
     onOpenChange: (open: boolean) => void
-    task: Task
+    task: TaskWithUser
     projectId: string
     members: Members[]
     onUpdate: (task: Task) => void
diff --git a/src/server/api/root.ts b/src/server/api/root.ts
index c25ebdb..87f8033 100644
--- a/src/server/api/root.ts
+++ b/src/server/api/root.ts
@@ -4,6 +4,7 @@ import { userRouter } from "./routers/user";
 import { invitationRouter } from "./routers/invitation";
 import { projectRouter } from "./routers/project";
 import { taskRouter } from "./routers/task";
+import { notificationRouter } from "./routers/notification";
 
 /**
  * This is the primary router for your server.
@@ -16,6 +17,7 @@ export const appRouter = createTRPCRouter({
   invitation: invitationRouter,
   project: projectRouter,
   task: taskRouter,
+  notification: notificationRouter,
 });
 
 // export type definition of API
diff --git a/src/server/api/routers/notification.ts b/src/server/api/routers/notification.ts
new file mode 100644
index 0000000..ca03b85
--- /dev/null
+++ b/src/server/api/routers/notification.ts
@@ -0,0 +1,77 @@
+import { z } from "zod"
+import { TRPCError } from "@trpc/server"
+import { createTRPCRouter, protectedProcedure } from "@/server/api/trpc"
+
+export const notificationRouter = createTRPCRouter({
+    // get
+    getMyNotifications: protectedProcedure
+        .query(async ({ ctx }) => {
+            return ctx.db.notification.findMany({
+                where: {
+                    userId: ctx.session.user.id,
+                },
+                orderBy: {
+                    createdAt: "desc",
+                },
+            });
+        }),
+
+    // get
+    getUnreadCount: protectedProcedure
+        .query(async ({ ctx }) => {
+            return ctx.db.notification.count({
+                where: {
+                    userId: ctx.session.user.id,
+                    isRead: false,
+                },
+            });
+        }),
+
+    // update
+    markAsRead: protectedProcedure
+        .input(z.object({ notificationId: z.string() }))
+        .mutation(async ({ ctx, input }) => {
+            const notification = await ctx.db.notification.findUnique({
+                where: {
+                    id: input.notificationId,
+                },
+            });
+
+            if (!notification) {
+                throw new TRPCError({
+                    code: "NOT_FOUND",
+                    message: "Notification not found",
+                });
+            }
+
+            if (notification.userId !== ctx.session.user.id) {
+                throw new TRPCError({
+                    code: "FORBIDDEN",
+                    message: "You don't have permission to mark this notification as read",
+                });
+            }
+
+            return ctx.db.notification.update({
+                where: {
+                    id: input.notificationId,
+                },
+                data: {
+                    isRead: true,
+                },
+            });
+        }),
+
+    // update
+    markAllAsRead: protectedProcedure
+        .mutation(async ({ ctx }) => {
+            return ctx.db.notification.updateMany({
+                where: {
+                    userId: ctx.session.user.id,
+                    isRead: false,
+                },
+                data: {
+                    isRead: true,
+                },
+            });
+        }),
+})
diff --git a/src/server/api/routers/task.ts b/src/server/api/routers/task.ts
index 5c3e926..b2ce834 100644
--- a/src/server/api/routers/task.ts
+++ b/src/server/api/routers/task.ts
@@ -1,6 +1,7 @@
 import { z } from "zod"
 import { TRPCError } from "@trpc/server"
 import { createTRPCRouter, protectedProcedure } from "@/server/api/trpc"
+import { ActivityType, NotificationType } from "@prisma/client"
 
 export const taskRouter = createTRPCRouter({
     create: protectedProcedure
@@ -58,7 +59,8 @@ export const taskRouter = createTRPCRouter({
                 }
             }
 
-            return ctx.db.task.create({
+            // create a task
+            const task = await ctx.db.task.create({
                 data: {
                     title: input.title,
                     description: input.description,
@@ -73,7 +75,51 @@ export const taskRouter = createTRPCRouter({
                     assignedTo: true,
                     createdBy: true,
                 },
-            })
+            });
+
+            // create activity
+            await ctx.db.activity.create({
+                data: {
+                    type: ActivityType.TASK_CREATED,
+                    description: `Task "${task.title}" was created by ${ctx.session.user.name}`,
+                    userId: ctx.session.user.id,
+                    projectId: input.projectId,
+                    taskId: task.id,
+                },
+            });
+
+            // create notification for assigned user
+            if (input.assignedToId) {
+
+                // create notification for assigned user
+                await ctx.db.notification.create({
+                    data: {
+                        type: NotificationType.TASK_ASSIGNED,
+                        message: `You were assigned to task "${task.title}"`,
+                        userId: input.assignedToId,
+                        metadata: {
+                            taskId: task.id,
+                            projectId: input.projectId,
+                        },
+                    },
+                });
+
+                // find assigned user name by Id
+                const user = await ctx.db.user.findUnique({ where: { id: input.assignedToId } });
+
+                // create activity for task assigned to user
+                await ctx.db.activity.create({
+                    data: {
+                        type: ActivityType.TASK_ASSIGNED,
+                        description: `${ctx.session.user.name} assigned this task to ${user?.name}`,
+                        userId: ctx.session.user.id,
+                        projectId: input.projectId,
+                        taskId: task.id,
+                    }
+                });
+            };
+
+            return task;
         }),
 
     getByProject: protectedProcedure
@@ -108,6 +154,10 @@ export const taskRouter = createTRPCRouter({
                 })
             }
 
+            // Note: if signedIn user is either project owner or admin ->  return all the tasks associated to project
+            // else if signedIn user is 'Member' -> return only following tasks:
+            // created by this user, or tasks assigned to this user or tagged tasks 
+
             if (isAdmin || isOwner) {
                 return await ctx.db.task.findMany({
                     where: {
@@ -136,7 +186,14 @@ export const taskRouter = createTRPCRouter({
                             },
                             {
                                 createdById: ctx.session.user.id,
-                            }
+                            },
+                            {
+                                tags: {
+                                    some: {
+                                        userId: ctx.session.user.id,
+                                    }
+                                },
+                            },
                         ]
                     },
                     include: {
@@ -165,6 +222,7 @@ export const taskRouter = createTRPCRouter({
                 status: z.enum(["TODO", "IN_PROGRESS", "DONE", "BACKLOG"]),
                 deadline: z.date(),
                 assignedToId: z.string().optional(),
+                taggedUserIds: z.array(z.string()).optional(),
             }),
         )
         .mutation(async ({ ctx, input }) => {
@@ -178,6 +236,7 @@ export const taskRouter = createTRPCRouter({
                             members: true,
                         },
                     },
+                    tags: true,
                 },
             })
 
@@ -189,6 +248,7 @@ export const taskRouter = createTRPCRouter({
             }
 
             // Check if user is a member or owner of the project
+            // Note: here we are just checking if user is a project member or not, role (like Admin, Member) both are part of project
             const isOwner = task.project.ownerId === ctx.session.user.id
             const isMember = task.project.members.some((member) => member.userId === ctx.session.user.id)
             const isCreator = task.createdById === ctx.session.user.id
@@ -198,7 +258,7 @@ export const taskRouter = createTRPCRouter({
                 throw new TRPCError({
                     code: "FORBIDDEN",
                     message: "You don't have access to this project",
-                })
+                });
             }
 
             // Only admin, owner, creator, or assignee can update the task
@@ -210,7 +270,7 @@ export const taskRouter = createTRPCRouter({
                 throw new TRPCError({
                     code: "FORBIDDEN",
                     message: "You don't have permission to update this task",
-                })
+                });
             }
 
             // If assignedToId is provided, check if the user is a member of the project
@@ -227,7 +287,29 @@ export const taskRouter = createTRPCRouter({
                 }
             }
 
-            return ctx.db.task.update({
+            // track changes for activity log
+            const changes = [];
+
+            if (task.title !== input.title) {
+                changes.push(`title from "${task.title}" to "${input.title}"`);
+            }
+            if (task.description !== input?.description) {
+                changes.push("description");
+            }
+            if (task.priority !== input.priority) {
+                changes.push(`priority from "${task.priority}" to "${input.priority}"`);
+            }
+            if (task.status !== input.status) {
+                changes.push(`status from "${task.status}" to "${input.status}"`);
+            }
+            if (task.deadline.toISOString() !== input.deadline.toISOString()) {
+                changes.push(`deadline from "${task.deadline.toISOString()}" to "${input.deadline.toISOString()}"`);
+            }
+            if (task.assignedToId !== input?.assignedToId) {
+                changes.push(`assignee`);
+            }
+
+            const updatedTask = await ctx.db.task.update({
                 where: {
                     id: input.taskId,
                 },
@@ -243,7 +325,150 @@ export const taskRouter = createTRPCRouter({
                     assignedTo: true,
                     createdBy: true,
                 },
-            })
+            });
+
+            // create activity for task update -> keeping track of all the updated information
+            if (changes.length > 0) {
+                await ctx.db.activity.create({
+                    data: {
+                        type: ActivityType.TASK_UPDATED,
+                        description: `Task "${updatedTask.title}" was updated: ${changes.join(", ")}`,
+                        userId: ctx.session.user.id,
+                        projectId: task.projectId,
+                        taskId: task.id,
+                        metadata: {
+                            changes,
+                        },
+                    },
+                });
+            }
+
+            // create notification for newly assigned user
+            if (input.assignedToId && input.assignedToId !== task.assignedToId) {
+                await ctx.db.notification.create({
+                    data: {
+                        type: NotificationType.TASK_ASSIGNED,
+                        message: `You were assigned to task "${updatedTask.title}"`,
+                        userId: input.assignedToId,
+                        metadata: {
+                            taskId: task.id,
+                            projectId: task.projectId,
+                        },
+                    },
+                });
+
+                // find assigned user name by Id
+                const user = await ctx.db.user.findUnique({ where: { id: input.assignedToId } });
+
+                // create activity for task assigned to user
+                await ctx.db.activity.create({
+                    data: {
+                        type: ActivityType.TASK_ASSIGNED,
+                        description: `${ctx.session.user.name} assigned this task to ${user?.name}`,
+                        userId: ctx.session.user.id,
+                        projectId: task.projectId,
+                        taskId: task.id,
+                    }
+                });
+            }
+            
+            // handle tagged users
+            if (input.taggedUserIds && input.taggedUserIds.length > 0) {
+
+                // get current tags
+                const currentTaggedUserIds = task.tags.map((tag) => tag.userId);
+
+                // find new users to tag
+                const newTaggedUserIds = input.taggedUserIds.filter((userId) => !currentTaggedUserIds.includes(userId));
+
+                // find users to untag
+                const userIdsToRemove = currentTaggedUserIds.filter((userId) => !input?.taggedUserIds?.includes(userId));
+
+                // validate that all new tagged users are members of the project
+                const validNewTaggedUserIds = newTaggedUserIds.filter(
+                    (userId) =>
+                        userId === task.project.ownerId || task.project.members.some((member) => member.userId === userId),
+                )
+
+                // remove tags for users no longer tagged
+                if (userIdsToRemove.length > 0) {
+                    // to delete multiple users either user Promise.all or deleteMany
+                    await ctx.db.taskTag.deleteMany({
+                        where: {
+                            taskId: task.id,
+                            userId: {
+                                in: userIdsToRemove,
+                            },
+                        },
+                    });
+                }
+
+                // add new tags
+                await Promise.all(
+                    validNewTaggedUserIds.map(async (userId) => {
+
+                        // do not tag the creator or assignee again
+
+                        if (userId !== task.createdById && userId !== input.assignedToId) {
+
+                            // entry in tasktag table
+                            await ctx.db.taskTag.create({
+                                data: {
+                                    taskId: task.id,
+                                    userId,
+                                },
+                            });
+
+                            // create notification for tagged user
+                            await ctx.db.notification.create({
+                                data: {
+                                    type: NotificationType.TASK_TAGGED,
+                                    message: `You were tagged in task "${updatedTask.title}"`,
+                                    userId,
+                                    metadata: {
+                                        taskId: task.id,
+                                        projectId: task.projectId,
+                                    },
+                                },
+                            });
+
+                            const userInfo = await ctx.db.user.findUnique({
+                                where: { id: userId }
+                            });
+
+                            // create activity for tagging
+                            await ctx.db.activity.create({
+                                data: {
+                                    type: ActivityType.TASK_TAGGED,
+                                    description: `${ctx.session.user.name} tagged ${userInfo?.name}`,
+                                    userId: ctx.session.user.id,
+                                    projectId: task.projectId,
+                                    taskId: task.id,
+                                    metadata: {
+                                        taggedUserId: userId,
+                                    },
+                                },
+                            });
+                        }
+                    }),
+                );
+            };
+
+            return await ctx.db.task.findUnique({
+                where: {
+                    id: task.id,
+                },
+                include: {
+                    assignedTo: true,
+                    createdBy: true,
+                    tags: {
+                        include: {
+                            user: true,
+                        },
+                    },
+                },
+            });
+
         }),
 
     updateStatus: protectedProcedure
@@ -285,14 +510,32 @@ export const taskRouter = createTRPCRouter({
                 })
             }
 
-            return ctx.db.task.update({
+            // update the task status
+            const updatedTask = ctx.db.task.update({
                 where: {
                     id: input.taskId,
                 },
                 data: {
                     status: input.status,
                 },
-            })
+            });
+
+            // create activity
+            await ctx.db.activity.create({
+                data: {
+                    type: ActivityType.TASK_STATUS_CHANGED,
+                    description: `Task "${task.title}" status changed from "${task.status}" to "${input.status}" by ${ctx.session.user.name}`,
+                    userId: ctx.session.user.id,
+                    projectId: task.projectId,
+                    taskId: task.id,
+                    metadata: {
+                        oldStatus: task.status,
+                        newStatus: input.status,
+                    },
+                },
+            });
+
+            return updatedTask;
         }),
 
     delete: protectedProcedure.input(z.object({ taskId: z.string() })).mutation(async ({ ctx, input }) => {
@@ -330,10 +573,71 @@ export const taskRouter = createTRPCRouter({
             })
         }
 
+        // create activity
+        await ctx.db.activity.create({
+            data: {
+                type: ActivityType.TASK_DELETED,
+                description: `Task "${task.title}" was deleted`,
+                userId: ctx.session.user.id,
+                projectId: task.projectId,
+                metadata: {
+                    taskId: task.id,
+                    taskTitle: task.title,
+                },
+            },
+        });
+
+        // delete task
         return ctx.db.task.delete({
             where: {
                 id: input.taskId,
             },
-        })
+        });
+    }),
+
+    getTaskActivities: protectedProcedure.input(z.object({ taskId: z.string() })).query(async ({ ctx, input }) => {
+        const task = await ctx.db.task.findUnique({
+            where: {
+                id: input.taskId,
+            },
+            include: {
+                project: {
+                    include: {
+                        members: true,
+                    },
+                },
+            },
+        });
+
+        if (!task) {
+            throw new TRPCError({
+                code: "NOT_FOUND",
+                message: "Task not found",
+            });
+        }
+
+        // check if user is a member or owner of the project
+        const isOwner = task.project.ownerId === ctx.session.user.id;
+        const isMember = task.project.members.some((member) => member.userId === ctx.session.user.id);
+
+        if (!isOwner && !isMember) {
+            throw new TRPCError({
+                code: "FORBIDDEN",
+                message: "You don't have access to this task",
+            });
+        }
+
+        return ctx.db.activity.findMany({
+            where: {
+                taskId: input.taskId,
+            },
+            include: {
+                user: true,
+            },
+            orderBy: {
+                createdAt: "desc",
+            },
+        });
     }),
+
 })