Drop third-party exceptions from PostHog autocapture

components/PostHogProvider.tsx

@@ -1,10 +1,35 @@
 "use client";
 
 import posthog from "posthog-js";
+import type { CaptureResult } from "posthog-js";
 import { PostHogProvider as PHProvider, usePostHog } from "posthog-js/react";
 import { usePathname, useSearchParams } from "next/navigation";
 import { useEffect, Suspense } from "react";
 
+// Third-party embeds (for example HubSpot) throw their own uncaught errors.
+// Exception autocapture reports these, but they are not app bugs. Drop any
+// exception whose every stack frame comes from one of these hosts.
+const THIRD_PARTY_ERROR_HOSTS = ["hscollectedforms.net", "hs-scripts.com"];
+
+function isThirdPartyException(event: CaptureResult): boolean {
+  const exceptions = event.properties?.$exception_list;
+  if (!Array.isArray(exceptions)) {
+    return false;
+  }
+
+  const frames = exceptions.flatMap(
+    (exception) => exception?.stacktrace?.frames ?? [],
+  );
+  if (frames.length === 0) {
+    return false;
+  }
+
+  return frames.every((frame) => {
+    const filename: string = frame?.filename ?? "";
+    return THIRD_PARTY_ERROR_HOSTS.some((host) => filename.includes(host));
+  });
+}
+
 export function PostHogProvider({ children }: { children: React.ReactNode }) {
   useEffect(() => {
     if (process.env.NEXT_PUBLIC_POSTHOG_KEY) {
@@ -14,6 +39,12 @@ export function PostHogProvider({ children }: { children: React.ReactNode }) {
         person_profiles: "always",
         capture_pageview: false,
         capture_pageleave: true,
+        before_send: (event) => {
+          if (event?.event === "$exception" && isThirdPartyException(event)) {
+            return null;
+          }
+          return event;
+        },
       });
     }
   }, []);