CodeChefVIT · abhitrueprogrammer · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026 · Aug 26, 2026
diff --git a/.env.example b/.env.example
@@ -30,4 +30,7 @@ GOOGLE_APPLICATION_CREDENTIALS_JSON=""      # The content of the JSON file you d
 
 # Upstash_Redis
 UPSTASH_REDIS_REST_URL=""           # REST URL of your Upstash Redis database
-UPSTASH_REDIS_REST_TOKEN=""         # REST API token for Upstash Redis
+UPSTASH_REDIS_REST_TOKEN=""         # REST API token for Upstash Redis
+
+NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN=""
+NEXT_PUBLIC_POSTHOG_HOST="https://e.papers.codechefvit.com"
diff --git a/package.json b/package.json
@@ -61,6 +61,8 @@
     "next-themes": "^0.3.0",
     "pdf-lib": "^1.17.1",
     "pdfjs-dist": "4.8.69",
+    "posthog-js": "^1.419.4",
+    "posthog-node": "^5.51.2",
     "prettier": "^3.5.3",
     "prettier-plugin-tailwindcss": "^0.6.11",
     "raw-loader": "^4.0.2",

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
diff --git a/src/app/api/request/route.ts b/src/app/api/request/route.ts
@@ -1,6 +1,8 @@
 import { success, failure } from "@/lib/utils/response";
-import { createPaperRequest } from "@/lib/services/paper"
-import type { CreatePaperInputType } from "@/lib/services/paper"
+import { createPaperRequest } from "@/lib/services/paper";
+import type { CreatePaperInputType } from "@/lib/services/paper";
+import { getPostHogClient } from "@/lib/posthog-server";
+import { randomUUID } from "crypto";
 
 export async function POST(req: Request) {
   try {
@@ -11,6 +13,21 @@ export async function POST(req: Request) {
     }
 
     const newRequest = await createPaperRequest({subject, exam, slot, year});
+
+    const posthog = getPostHogClient();
+    if (posthog) {
+      posthog.capture({
+        distinctId: randomUUID(),
+        event: "paper_request_created",
+        properties: {
+          exam,
+          slot,
+          year,
+        },
+      });
+      await posthog.flush();
+    }
+
     return success({ message: "Paper request submitted successfully!", request: newRequest }, "Created", 201);
   } catch (error) {
     console.error("Error creating paper request:", error);

diff --git a/src/app/api/upload/route.ts b/src/app/api/upload/route.ts
@@ -1,5 +1,7 @@
 import { success, failure } from "@/lib/utils/response";
 import { uploadPaper } from "@/lib/services/upload";
+import { getPostHogClient } from "@/lib/posthog-server";
+import { randomUUID } from "crypto";
 
 export const runtime = "nodejs";
 
@@ -21,6 +23,20 @@ export async function POST(req: Request) {
       return failure(result.message, result.status);
     }
 
+    const posthog = getPostHogClient();
+    if (posthog) {
+      posthog.capture({
+        distinctId: randomUUID(),
+        event: "paper_upload_completed",
+        properties: {
+          file_count: files.length,
+          is_pdf: isPdf,
+          campus: campus ?? "unknown",
+        },
+      });
+      await posthog.flush();
+    }
+
     return success(
       { file_url: result.file_url, thumbnail_url: result.thumbnail_url },
       "Created",

diff --git a/src/app/layout.tsx b/src/app/layout.tsx
@@ -8,6 +8,7 @@ import Navbar from "@/components/Navbar";
 import Footer from "@/components/Footer";
 import ChildrenWrapper from "@/components/ChildrenWrapper";
 import { CoursesProvider } from "@/context/courseContext";
+import { PostHogProvider } from "@/components/PostHogProvider";
 
 export const metadata: Metadata = {
   metadataBase: new URL("https://papers.codechefvit.com/"),
@@ -113,21 +114,23 @@ export default function RootLayout({
         </Script>
       </head>
       <body>
-        <ThemeProvider
-          attribute="class"
-          defaultTheme="dark"
-          enableSystem
-          disableTransitionOnChange
-        >
-          <Toaster position="top-right" reverseOrder={false} />
-          <div className="bg-[#F3F5FF] dark:bg-[#070114]">
-            <CoursesProvider>
-              <Navbar />
-              <ChildrenWrapper>{children}</ChildrenWrapper>
-              <Footer />
-            </CoursesProvider>
-          </div>
-        </ThemeProvider>
+        <PostHogProvider>
+          <ThemeProvider
+            attribute="class"
+            defaultTheme="dark"
+            enableSystem
+            disableTransitionOnChange
+          >
+            <Toaster position="top-right" reverseOrder={false} />
+            <div className="bg-[#F3F5FF] dark:bg-[#070114]">
+              <CoursesProvider>
+                <Navbar />
+                <ChildrenWrapper>{children}</ChildrenWrapper>
+                <Footer />
+              </CoursesProvider>
+            </div>
+          </ThemeProvider>
+        </PostHogProvider>
       </body>
     </html>
   );

diff --git a/src/components/CatalogueContent.tsx b/src/components/CatalogueContent.tsx
@@ -16,6 +16,7 @@ import SearchBarChild from "./Searchbar/searchbar-child";
 import Link from "next/link";
 import { useCourses } from "@/context/courseContext";
 import { FilterProvider, useFilters } from "@/context/filterContext";
+import posthog from "posthog-js";
 import EmptyState from "./ui/EmptyState";
 import SelectionToolbar from "./SelectionToolbar";
 import SortComponent from "./ui/sorting";
@@ -143,6 +144,10 @@ const CatalogueContentInner = ({ subject }: { subject: string | null }) => {
       : saved.filter((s) => s !== subject);
 
     localStorage.setItem("userSubjects", JSON.stringify(updated));
+
+    posthog.capture(current ? "subject_pinned" : "subject_unpinned", {
+      subject: subject?.split(" [")[0]?.trim() ?? subject,
+    });
   };
 
   // Fetch papers ONLY when subject changes (not when filters change!)

diff --git a/src/components/Footer.tsx b/src/components/Footer.tsx
@@ -15,6 +15,7 @@ import {
 import { Mail } from "lucide-react";
 import toast from "react-hot-toast";
 import type { ApiResponse } from '@/interface'
+import posthog from "posthog-js";
 
 export default function Footer() {
   const [email, setEmail] = useState("");
@@ -42,6 +43,8 @@ export default function Footer() {
       },
     );
 
+    posthog.capture("newsletter_subscribed");
+
     setEmail("");
   };
 

diff --git a/src/components/PostHogProvider.tsx b/src/components/PostHogProvider.tsx
@@ -0,0 +1,29 @@
+"use client";
+
+import posthog from "posthog-js";
+import { PostHogProvider as PHProvider } from "posthog-js/react";
+import { useEffect } from "react";
+
+export function PostHogProvider({ children }: { children: React.ReactNode }) {
+  useEffect(() => {
+    const token = process.env.NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN;
+    const host = process.env.NEXT_PUBLIC_POSTHOG_HOST;
+    if (!token || !host) {
+      if (process.env.NODE_ENV !== "production") {
+        console.error(
+          "NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN and NEXT_PUBLIC_POSTHOG_HOST variables required by PostHog are missing or un-configured, this causes events to be silently missed. This error stops appearing once both variables are configured",
+        );
+      }
+      return;
+    }
+    posthog.init(token, {
+      api_host: host,
+      ui_host: "https://us.posthog.com",
+      defaults: "2026-01-30",
+      capture_exceptions: true,
+      debug: process.env.NODE_ENV === "development",
+    });
+  }, []);
+
+  return <PHProvider client={posthog}>{children}</PHProvider>;
+}
diff --git a/src/components/ReportTagModal.tsx b/src/components/ReportTagModal.tsx
@@ -15,7 +15,8 @@ import { MultiSelect } from "@/components/multi-select";
 import LabeledInput from "@/components/ui/LabeledInput";
 import LabeledSelect from "@/components/ui/LabeledSelect";
 import axios from "axios";
-import toast from "react-hot-toast";  
+import toast from "react-hot-toast";
+import posthog from "posthog-js";
 import { type ApiResponse } from '@/interface'
 
 type ReportResponse = ApiResponse<{ error?: string; message?: string }>;
@@ -236,6 +237,11 @@ if (reportedFields.length === 0 && comment.trim().length === 0) {
     }
   )
   .then(() => {
+      posthog.capture("paper_reported", {
+        fields_reported: reportedFields.map((f) => f.field),
+        fields_reported_count: reportedFields.length,
+        has_comment: comment.trim().length > 0,
+      });
       modalSetOpen(false);
       setComment("");
       setEmail("");

diff --git a/src/components/ShareButton.tsx b/src/components/ShareButton.tsx
@@ -15,6 +15,7 @@ import { FaShare } from "react-icons/fa";
 import QR from "./qr";
 import { Button } from "./ui/button";
 import { usePathname } from "next/navigation";
+import posthog from "posthog-js";
 
 interface ShareButtonProps {
   isFullscreen: boolean;
@@ -63,6 +64,7 @@ export default function ShareButton({ isFullscreen, viewerRef }: ShareButtonProp
                 loading: "Copying link...",
                 error: "Error copying link",
               });
+              posthog.capture("paper_shared", { method: "link_copied" });
             }}
           >
             <p>Copy Link To Clipboard</p>

diff --git a/src/components/newPdfViewer.tsx b/src/components/newPdfViewer.tsx
@@ -10,6 +10,7 @@
   import { ExportPluginPackage }                           from '@embedpdf/plugin-export/react';
 
   import { Download, ZoomIn, ZoomOut, Maximize2, Minimize2, BookOpenText, X } from "lucide-react";
+  import posthog from "posthog-js";
   import { memo, useCallback, useEffect, useMemo, useRef, useState } from "react";
   import { downloadFile } from "../lib/utils/download";
   import { Button } from "./ui/button";
@@ -478,6 +479,9 @@
         paper_title: name,
         paper_url: url,
       });
+      posthog.capture("paper_downloaded", {
+        paper_name: name,
+      });
       await downloadFile(url, `${name}.pdf`);
     }, [url, name]);
 
@@ -508,6 +512,7 @@
     const toggleReadingMode = useCallback(() => {
       setIsReadingMode((r) => {
         const next = !r;
+        posthog.capture("reading_mode_toggled", { enabled: next });
         onReadingModeChange?.(next);
         return next;
       });

diff --git a/src/context/filterContext.tsx b/src/context/filterContext.tsx
@@ -14,6 +14,7 @@ import {
   useSearchParams,
 } from "next/navigation";
 import { type IPaper, type Filters } from "@/interface";
+import posthog from "posthog-js";
 import JSZip from "jszip";
 import { toast } from "react-hot-toast";
 import { getSecureUrl, generateFileName } from "@/lib/utils/download";
@@ -208,6 +209,12 @@ export const FilterProvider: React.FC<FilterProviderProps> = ({
       a.remove();
       URL.revokeObjectURL(url);
 
+      posthog.capture("papers_bulk_downloaded", {
+        download_count: uniquePapers.length - failedCount,
+        total_selected: uniquePapers.length,
+        failed_count: failedCount,
+      });
+
       if (failedCount > 0) {
         toast.success(
           `Downloaded ${uniquePapers.length - failedCount} of ${uniquePapers.length} papers (${failedCount} failed).`,

diff --git a/src/lib/posthog-server.ts b/src/lib/posthog-server.ts
@@ -0,0 +1,21 @@
+import { PostHog } from "posthog-node";
+
+let posthogClient: PostHog | null = null;
+
+export function getPostHogClient(): PostHog | null {
+  const token = process.env.NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN;
+  if (!token) {
+    if (process.env.NODE_ENV !== "production") {
+      console.error(
+        "NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN variable required by PostHog is missing or un-configured, this causes events to be silently missed. This error stops appearing once NEXT_PUBLIC_POSTHOG_PROJECT_TOKEN is configured",
+      );
+    }
+    return null;
+  }
+  posthogClient ??= new PostHog(token, {
+    host: process.env.NEXT_PUBLIC_POSTHOG_HOST,
+    flushAt: 1,
+    flushInterval: 0,
+  });
+  return posthogClient;
+}