From 752d31d846fd0af9ad3d5a3331f94a7b985a6710 Mon Sep 17 00:00:00 2001
From: Hubert Sosinski <hubert.sosinski@callstack.com>
Date: Thu, 27 Nov 2025 17:56:44 +0100
Subject: [PATCH] disable sending Firebase marks to Sentry

---
 .../middlewares/firebasePerformanceFilter.ts  | 22 +++++++++++++++++++
 src/libs/telemetry/middlewares/index.ts       |  3 ++-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 src/libs/telemetry/middlewares/firebasePerformanceFilter.ts

diff --git a/src/libs/telemetry/middlewares/firebasePerformanceFilter.ts b/src/libs/telemetry/middlewares/firebasePerformanceFilter.ts
new file mode 100644
index 000000000000..fdc17784b63b
--- /dev/null
+++ b/src/libs/telemetry/middlewares/firebasePerformanceFilter.ts
@@ -0,0 +1,22 @@
+import type {TransactionEvent} from '@sentry/core';
+import type {TelemetryBeforeSend} from './index';
+
+/**
+ * Drop Firebase Performance user timing spans (FB-PERF-TRACE-*)
+ * to avoid noisy mark/measure spans in Sentry.
+ */
+const firebasePerformanceFilter: TelemetryBeforeSend = (event: TransactionEvent): TransactionEvent => {
+    if (!event.spans) {
+        return event;
+    }
+
+    const spans = event.spans.filter((span) => {
+        const description = span.description ?? '';
+
+        return !description.includes('FB-PERF-TRACE');
+    });
+
+    return {...event, spans};
+};
+
+export default firebasePerformanceFilter;
diff --git a/src/libs/telemetry/middlewares/index.ts b/src/libs/telemetry/middlewares/index.ts
index 22dd601b5419..4f4f0ae3fbf6 100644
--- a/src/libs/telemetry/middlewares/index.ts
+++ b/src/libs/telemetry/middlewares/index.ts
@@ -1,9 +1,10 @@
 import type {EventHint, TransactionEvent} from '@sentry/core';
 import emailDomainFilter from './emailDomainFilter';
+import firebasePerformanceFilter from './firebasePerformanceFilter';
 
 type TelemetryBeforeSend = (event: TransactionEvent, hint: EventHint) => TransactionEvent | null | Promise<TransactionEvent | null>;
 
-const middlewares: TelemetryBeforeSend[] = [emailDomainFilter];
+const middlewares: TelemetryBeforeSend[] = [emailDomainFilter, firebasePerformanceFilter];
 
 function processBeforeSendTransactions(event: TransactionEvent, hint: EventHint): Promise<TransactionEvent | null> {
     return middlewares.reduce(