From e7066130b85eb54acae2aed7c4774197ab122e82 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Mon, 24 Nov 2025 13:54:47 +0100
Subject: [PATCH 1/7] Metrics for React Native SDK

---
 packages/core/src/js/index.ts          |  1 +
 packages/core/src/js/wrapper.ts        |  1 +
 packages/core/test/wrapper.test.ts     | 18 ++++++++++++++++++
 samples/expo/app/(tabs)/index.tsx      | 18 +++++++++++++++++-
 samples/expo/app/_layout.tsx           |  7 ++++++-
 samples/react-native-macos/src/App.tsx |  4 ++++
 samples/react-native/src/App.tsx       |  4 ++++
 7 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/packages/core/src/js/index.ts b/packages/core/src/js/index.ts
index 4a475a33c1..d43df01c5f 100644
--- a/packages/core/src/js/index.ts
+++ b/packages/core/src/js/index.ts
@@ -46,6 +46,7 @@ export {
   setCurrentClient,
   addEventProcessor,
   lastEventId,
+  metrics,
 } from '@sentry/core';
 
 export {
diff --git a/packages/core/src/js/wrapper.ts b/packages/core/src/js/wrapper.ts
index d84e61a632..3ac01e6498 100644
--- a/packages/core/src/js/wrapper.ts
+++ b/packages/core/src/js/wrapper.ts
@@ -281,6 +281,7 @@ export const NATIVE: SentryNativeWrapper = {
       beforeSend,
       beforeBreadcrumb,
       beforeSendTransaction,
+      beforeSendMetric,
       integrations,
       ignoreErrors,
       logsOrigin,
diff --git a/packages/core/test/wrapper.test.ts b/packages/core/test/wrapper.test.ts
index a27b13bdc8..8b2ead16c9 100644
--- a/packages/core/test/wrapper.test.ts
+++ b/packages/core/test/wrapper.test.ts
@@ -194,6 +194,24 @@ describe('Tests Native Wrapper', () => {
       expect(NATIVE.enableNative).toBe(true);
     });
 
+    test('filter beforeSendMetric when initializing Native SDK', async () => {
+      await NATIVE.initNativeSdk({
+        dsn: 'test',
+        enableNative: true,
+        autoInitializeNativeSdk: true,
+        beforeSendMetric: jest.fn(),
+        devServerUrl: undefined,
+        defaultSidecarUrl: undefined,
+        mobileReplayOptions: undefined,
+      });
+
+      expect(RNSentry.initNativeSdk).toHaveBeenCalled();
+      // @ts-expect-error mock value
+      const initParameter = RNSentry.initNativeSdk.mock.calls[0][0];
+      expect(initParameter).not.toHaveProperty('beforeSendMetric');
+      expect(NATIVE.enableNative).toBe(true);
+    });
+
     test('filter integrations when initializing Native SDK', async () => {
       await NATIVE.initNativeSdk({
         dsn: 'test',
diff --git a/samples/expo/app/(tabs)/index.tsx b/samples/expo/app/(tabs)/index.tsx
index 68745d776c..15b25a0dd9 100644
--- a/samples/expo/app/(tabs)/index.tsx
+++ b/samples/expo/app/(tabs)/index.tsx
@@ -39,6 +39,22 @@ export default function TabOneScreen() {
             }}
           />
         </View>
+        <View style={styles.buttonWrapper}>
+          <Button
+            title="Metrics count: Increase"
+            onPress={() => {
+              Sentry.metrics.count('sentry_rn_test_metric', 1);
+            }}
+          />
+        </View>
+        <View style={styles.buttonWrapper}>
+          <Button
+            title="Metrics count: Increase by 100"
+            onPress={() => {
+              Sentry.metrics.count('sentry_rn_test_metric', 100);
+            }}
+          />
+        </View>
         <View style={styles.buttonWrapper}>
           <Button
             title="Capture exception"
@@ -202,7 +218,7 @@ export default function TabOneScreen() {
               Sentry.logger.warn('expo warn log');
               Sentry.logger.error('expo error log');
 
-              Sentry.logger.info('expo info log with data', { database: 'admin', number: 123, obj: { password: 'admin'} });
+              Sentry.logger.info('expo info log with data', { database: 'admin', number: 123, obj: { password: 'admin' } });
             }}
           />
         </View>
diff --git a/samples/expo/app/_layout.tsx b/samples/expo/app/_layout.tsx
index 7e84d27ef6..d1483b6d77 100644
--- a/samples/expo/app/_layout.tsx
+++ b/samples/expo/app/_layout.tsx
@@ -28,7 +28,7 @@ const navigationIntegration = Sentry.reactNavigationIntegration({
 
 Sentry.init({
   // Replace the example DSN below with your own DSN:
-  dsn: SENTRY_INTERNAL_DSN,
+  dsn: 'https://c96d5b6136315b7a6cef6230a38b4842@o4509786567475200.ingest.de.sentry.io/4510182962298960',
   debug: true,
   environment: 'dev',
   enableLogs: true,
@@ -40,6 +40,11 @@ Sentry.init({
     console.log('Transaction beforeSend:', event.event_id);
     return event;
   },
+  beforeSendMetric: (metric: Sentry.Metric) => {
+    console.log('Metric beforeSend:', metric.name, metric.value);
+    return metric;
+  },
+  enableMetrics: false,
   // This will be called with a boolean `didCallNativeInit` when the native SDK has been contacted.
   onReady: ({ didCallNativeInit }) => {
     console.log('onReady called with didCallNativeInit:', didCallNativeInit);
diff --git a/samples/react-native-macos/src/App.tsx b/samples/react-native-macos/src/App.tsx
index 817d538efc..a12e51d5f7 100644
--- a/samples/react-native-macos/src/App.tsx
+++ b/samples/react-native-macos/src/App.tsx
@@ -54,6 +54,10 @@ Sentry.init({
     logWithoutTracing('Transaction beforeSend:', event.event_id);
     return event;
   },
+  beforeSendMetric(metric: Sentry.Metric) {
+    logWithoutTracing('Metric beforeSend:', metric.name, metric.value);
+    return metric;
+  },
   // This will be called with a boolean `didCallNativeInit` when the native SDK has been contacted.
   onReady: ({ didCallNativeInit }) => {
     logWithoutTracing(
diff --git a/samples/react-native/src/App.tsx b/samples/react-native/src/App.tsx
index 8974c90206..b7f4db4ce7 100644
--- a/samples/react-native/src/App.tsx
+++ b/samples/react-native/src/App.tsx
@@ -57,6 +57,10 @@ Sentry.init({
     logWithoutTracing('Transaction beforeSend:', event.event_id);
     return event;
   },
+  beforeSendMetric(metric: Sentry.Metric) {
+    logWithoutTracing('Metric beforeSend:', metric.name, metric.value);
+    return metric;
+  },
   // This will be called with a boolean `didCallNativeInit` when the native SDK has been contacted.
   onReady: ({ didCallNativeInit }) => {
     logWithoutTracing(

From 713d14601566a90827b6bb96af5281714d95a43b Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 10:17:00 +0100
Subject: [PATCH 2/7] Fixes

# Conflicts:
#	samples/expo/package.json
---
 packages/core/src/js/client.ts    |  1 +
 samples/expo/app/(tabs)/index.tsx | 40 ++++++++++++++++++-------------
 samples/expo/app/_layout.tsx      |  4 ++--
 3 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/packages/core/src/js/client.ts b/packages/core/src/js/client.ts
index 42f3659c2e..029128e7be 100644
--- a/packages/core/src/js/client.ts
+++ b/packages/core/src/js/client.ts
@@ -73,6 +73,7 @@ export class ReactNativeClient extends Client<ReactNativeClientOptions> {
       options.enableLogs = false;
     }
 
+
     super(options);
 
     this._outcomesBuffer = [];
diff --git a/samples/expo/app/(tabs)/index.tsx b/samples/expo/app/(tabs)/index.tsx
index 15b25a0dd9..0aa94be894 100644
--- a/samples/expo/app/(tabs)/index.tsx
+++ b/samples/expo/app/(tabs)/index.tsx
@@ -39,22 +39,6 @@ export default function TabOneScreen() {
             }}
           />
         </View>
-        <View style={styles.buttonWrapper}>
-          <Button
-            title="Metrics count: Increase"
-            onPress={() => {
-              Sentry.metrics.count('sentry_rn_test_metric', 1);
-            }}
-          />
-        </View>
-        <View style={styles.buttonWrapper}>
-          <Button
-            title="Metrics count: Increase by 100"
-            onPress={() => {
-              Sentry.metrics.count('sentry_rn_test_metric', 100);
-            }}
-          />
-        </View>
         <View style={styles.buttonWrapper}>
           <Button
             title="Capture exception"
@@ -134,6 +118,30 @@ export default function TabOneScreen() {
             }}
           />
         </View>
+        <View style={styles.buttonWrapper}>
+          <Button
+            title="Send count metric"
+            onPress={() => {
+              Sentry.metrics.count('count_metric', 1);
+            }}
+          />
+        </View>
+        <View style={styles.buttonWrapper}>
+          <Button
+            title="Send distribution metric"
+            onPress={() => {
+              Sentry.metrics.count('distribution_metric', 100);
+            }}
+          />
+        </View>
+        <View style={styles.buttonWrapper}>
+          <Button
+            title="Send count metric with attributes"
+            onPress={() => {
+              Sentry.metrics.count('count_metric', 1, { attributes: { from_test_app: true } });
+            }}
+          />
+        </View>
         <View style={styles.buttonWrapper}>
           <Button
             title="Flush"
diff --git a/samples/expo/app/_layout.tsx b/samples/expo/app/_layout.tsx
index d1483b6d77..121a5284a0 100644
--- a/samples/expo/app/_layout.tsx
+++ b/samples/expo/app/_layout.tsx
@@ -28,7 +28,7 @@ const navigationIntegration = Sentry.reactNavigationIntegration({
 
 Sentry.init({
   // Replace the example DSN below with your own DSN:
-  dsn: 'https://c96d5b6136315b7a6cef6230a38b4842@o4509786567475200.ingest.de.sentry.io/4510182962298960',
+  dsn: SENTRY_INTERNAL_DSN,
   debug: true,
   environment: 'dev',
   enableLogs: true,
@@ -44,7 +44,7 @@ Sentry.init({
     console.log('Metric beforeSend:', metric.name, metric.value);
     return metric;
   },
-  enableMetrics: false,
+  enableMetrics: true,
   // This will be called with a boolean `didCallNativeInit` when the native SDK has been contacted.
   onReady: ({ didCallNativeInit }) => {
     console.log('onReady called with didCallNativeInit:', didCallNativeInit);

From 8ccda2b776a1f911ce6ecf71bf7ee37ade8f2167 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 10:35:41 +0100
Subject: [PATCH 3/7] Fixes, changelog entry


 Conflicts:

	CHANGELOG.md
---
 packages/core/test/metrics.test.ts | 179 +++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 packages/core/test/metrics.test.ts

diff --git a/packages/core/test/metrics.test.ts b/packages/core/test/metrics.test.ts
new file mode 100644
index 0000000000..eb911803fd
--- /dev/null
+++ b/packages/core/test/metrics.test.ts
@@ -0,0 +1,179 @@
+import { getClient, metrics, setCurrentClient } from '@sentry/core';
+import { ReactNativeClient } from '../src/js';
+import { getDefaultTestClientOptions, TestClient } from './mocks/client';
+import { NATIVE } from './mockWrapper';
+
+jest.mock('../src/js/wrapper', () => jest.requireActual('./mockWrapper'));
+
+const EXAMPLE_DSN = 'https://6890c2f6677340daa4804f8194804ea2@o19635.ingest.sentry.io/148053';
+
+describe('Metrics', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    jest.useFakeTimers();
+    (NATIVE.isNativeAvailable as jest.Mock).mockImplementation(() => true);
+  });
+
+  afterEach(() => {
+    jest.runOnlyPendingTimers();
+    jest.useRealTimers();
+    getClient()?.close();
+  });
+
+  describe('beforeSendMetric', () => {
+    it('is called when enableMetrics is true and a metric is sent', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+    });
+
+    it('is not called when enableMetrics is false', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: false,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).not.toHaveBeenCalled();
+    });
+
+    it('is called when enableMetrics is undefined (metrics are enabled by default)', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+    });
+
+    it('allows beforeSendMetric to modify metrics when enableMetrics is true', async () => {
+      const beforeSendMetric = jest.fn(metric => {
+        // Modify the metric
+        return { ...metric, name: 'modified_metric' };
+      });
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      const modifiedMetric = beforeSendMetric.mock.results[0]?.value;
+      expect(modifiedMetric).toBeDefined();
+      expect(modifiedMetric.name).toBe('modified_metric');
+    });
+
+    it('allows beforeSendMetric to drop metrics by returning null', async () => {
+      const beforeSendMetric = jest.fn(() => null);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric
+      metrics.count('test_metric', 1);
+
+      // Advance timers
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      expect(beforeSendMetric.mock.results[0]?.value).toBeNull();
+    });
+  });
+
+  describe('metrics API', () => {
+    it('metrics.count works when enableMetrics is true', () => {
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      expect(() => {
+        metrics.count('test_metric', 1);
+      }).not.toThrow();
+    });
+
+    it('metrics can be sent with tags', async () => {
+      const beforeSendMetric = jest.fn(metric => metric);
+
+      const client = new ReactNativeClient({
+        ...getDefaultTestClientOptions({
+          dsn: EXAMPLE_DSN,
+          enableMetrics: true,
+          beforeSendMetric,
+        }),
+      });
+
+      setCurrentClient(client);
+      client.init();
+
+      // Send a metric with tags
+      metrics.count('test_metric', 1, {
+        attributes: { environment: 'test' },
+      });
+
+      jest.advanceTimersByTime(10000);
+      expect(beforeSendMetric).toHaveBeenCalled();
+      const sentMetric = beforeSendMetric.mock.calls[0]?.[0];
+      expect(sentMetric).toBeDefined();
+    });
+  });
+});

From d327971592bbae39599f634420c871ea9ecd8478 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 10:40:16 +0100
Subject: [PATCH 4/7] Metrics changelog

---
 CHANGELOG.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f586bdf517..92386a8928 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,10 @@
 
 ## Unreleased
 
+### Features
+
+- Adds metrics ([#5402](https://github.com/getsentry/sentry-react-native/pull/5402))
+
 ### Dependencies
 
 - Bump Android SDK from v8.27.0 to v8.27.1 ([#5404](https://github.com/getsentry/sentry-react-native/pull/5404))

From b763d55cf4f22cf9111df91c5827b3e76c18b0ff Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 10:41:05 +0100
Subject: [PATCH 5/7] Smallish fix

---
 packages/core/src/js/client.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/core/src/js/client.ts b/packages/core/src/js/client.ts
index 029128e7be..42f3659c2e 100644
--- a/packages/core/src/js/client.ts
+++ b/packages/core/src/js/client.ts
@@ -73,7 +73,6 @@ export class ReactNativeClient extends Client<ReactNativeClientOptions> {
       options.enableLogs = false;
     }
 
-
     super(options);
 
     this._outcomesBuffer = [];

From 8a8c1bfa7adf0facf9e4a25b71414558eeabc663 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 10:46:09 +0100
Subject: [PATCH 6/7] Lint fix

---
 packages/core/test/metrics.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/core/test/metrics.test.ts b/packages/core/test/metrics.test.ts
index eb911803fd..3e0e310ecc 100644
--- a/packages/core/test/metrics.test.ts
+++ b/packages/core/test/metrics.test.ts
@@ -1,6 +1,6 @@
 import { getClient, metrics, setCurrentClient } from '@sentry/core';
 import { ReactNativeClient } from '../src/js';
-import { getDefaultTestClientOptions, TestClient } from './mocks/client';
+import { getDefaultTestClientOptions } from './mocks/client';
 import { NATIVE } from './mockWrapper';
 
 jest.mock('../src/js/wrapper', () => jest.requireActual('./mockWrapper'));

From 190a7ba2b43c18252a48caacc158552da48ef4e5 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Tue, 25 Nov 2025 11:05:24 +0100
Subject: [PATCH 7/7] Fix

---
 packages/core/test/metrics.test.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/core/test/metrics.test.ts b/packages/core/test/metrics.test.ts
index 3e0e310ecc..e1e7bc1de1 100644
--- a/packages/core/test/metrics.test.ts
+++ b/packages/core/test/metrics.test.ts
@@ -15,9 +15,10 @@ describe('Metrics', () => {
   });
 
   afterEach(() => {
-    jest.runOnlyPendingTimers();
+    const client = getClient();
+    client?.close();
+    jest.clearAllTimers();
     jest.useRealTimers();
-    getClient()?.close();
   });
 
   describe('beforeSendMetric', () => {