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React Native RUM SDK

Install and configure the Last9 React Native RUM SDK. TypeScript API, CDN-hosted npm tarball, bridges native Android and iOS SDKs. Auto-instruments fetch/XHR, React Navigation, errors, ANRs.

Real User Monitoring for React Native apps. Automatic instrumentation for sessions, views, network requests (fetch/XHR), errors, and resource metrics via OpenTelemetry. ANR detection is available on Android only.

The React Native SDK wraps the Android and iOS native SDKs. Each platform’s CDN repo must be configured so the native dependencies resolve.

Prerequisites

  • React Native >= 0.74
  • iOS 15.1+
  • Android minSdk 21 (Android 5.0+)
  • Native dependencies:
    • Android: io.last9:rum-android:0.7.0 (resolved from CDN Maven)
    • iOS: Last9RUM 0.7.0 (resolved from CDN podspec)

CDN artifacts

ArtifactURL
Tarballhttps://cdn.last9.io/rum-sdk/react-native/builds/0.7.0/last9-rum-react-native-0.7.0.tgz
Checksumhttps://cdn.last9.io/rum-sdk/react-native/builds/0.7.0/last9-rum-react-native-0.7.0.tgz.sha256

Staging builds use the -alpha.<run_number> suffix.

Installation

  1. Install the package

    npm install https://cdn.last9.io/rum-sdk/react-native/builds/0.7.0/last9-rum-react-native-0.7.0.tgz
  2. Android — add the CDN Maven repository

    In android/settings.gradle (or android/build.gradle):

    dependencyResolutionManagement {
    repositories {
    google()
    mavenCentral()
    maven { url = uri("https://cdn.last9.io/rum-sdk/android/maven/") }
    }
    }
  3. iOS — add the Last9RUM podspec

    In ios/Podfile:

    pod 'Last9RUM', :podspec => 'https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.podspec'

    Then install pods:

    cd ios && pod install
  4. Initialize the SDK

    At app entry (before any screens render):

    import { L9Rum } from "@last9/rum-react-native";
    L9Rum.initialize({
    baseUrl: "https://otlp-ext-aps1.last9.io/v1/otlp/organizations/<org>",
    origin: "https://app.last9.io",
    clientToken: "your-client-token",
    serviceName: "my-rn-app",
    serviceVersion: "1.0.0",
    deploymentEnvironment: "production",
    });

Configuration

L9Rum.initialize({
// --- Required ---------------------------------------------------------
// OTLP collector endpoint
baseUrl: "https://otlp-ext-aps1.last9.io/v1/otlp/organizations/<org>",
// Authentication token from Last9
clientToken: "your-client-token",
// Application identifier (maps to service.name)
serviceName: "my-rn-app",
// App version string (maps to service.version)
serviceVersion: "1.0.0",
// Environment name
deploymentEnvironment: "production",
// --- Optional ---------------------------------------------------------
// Origin sent as X-LAST9-ORIGIN header.
// Required for client_monitoring tokens.
origin: "https://app.last9.io",
// Specific build identifier (maps to app.build_id)
appBuildId: "1.0.0-build-42",
// Unique per-install ID (NOT a hardware ID). Persists across launches.
appInstallationId: undefined,
// Session sampling rate: 0-100 (percentage). 100 = sample everything.
sampleRate: 100,
// Print debug logs to console
debugLogs: false,
// Automatically instrument network requests through native hooks
networkInstrumentation: true,
// Automatically capture unhandled JS errors
errorInstrumentation: true,
// Max spans per export batch
maxExportBatchSize: 100,
// Export timeout in milliseconds
exportTimeoutMs: 30000,
// ANR detection (Android only)
anrDetectionEnabled: true,
anrThresholdMs: 5000,
// Periodically sample memory and CPU
resourceMonitoringEnabled: true,
resourceSamplingIntervalMs: 30000,
// Setting this to true will hide network requests (and their
// DNS/TCP/TLS/TTFB phase child spans) from the Last9 dashboard's
// Sessions → APIs tab. Each request would get its own traceId
// instead of sharing the current view's traceId, and that tab
// only fetches spans that share the View's traceId. Keep this
// false unless you specifically need per-request trace isolation.
isolateTracePerRequest: false,
// Fine-grained network ignore rules. Strings use substring matching;
// RegExp uses regex search semantics. Matched URLs are dropped before
// span creation.
ignorePatterns: {
fullUrl: [
'https://cdn.example.com',
/^https:\/\/.*\.example\.com/i,
],
pathname: [
'.pdf',
'.jpg',
/^\/internal\/metrics/,
],
hostname: [
'cdn.example.com',
/(^|\.)assets\.example\.com$/i,
],
},
// 'preserve' (default): keep traceparent on ignored requests.
// 'strip': remove traceparent from ignored requests.
propagationMode: 'preserve',
// Custom resource attributes added to every span
resourceAttributes: {
"app.platform": "react-native",
},
// W3C Baggage propagation on outgoing requests
baggage: {
enabled: false,
allowedKeys: ["session.id", "user.id"],
maxTotalBytes: 8192,
warnAtPercentage: 80,
},
});

Network ignore patterns

Skip noisy URLs before span creation by matching against full URL, pathname, or hostname. Strings use substring matching; RegExp uses regex search semantics.

L9Rum.initialize({
ignorePatterns: {
fullUrl: [
'https://cdn.example.com',
/^https:\/\/.*\.example\.com/i,
],
pathname: ['.pdf', '.jpg', /^\/internal\/metrics/],
hostname: ['cdn.example.com', /(^|\.)assets\.example\.com$/i],
},
// 'preserve' (default): keep traceparent on ignored requests.
// 'strip': remove traceparent from ignored requests.
propagationMode: 'strip',
});

Network phase child spans

Network instrumentation is native by default so the SDK emits child spans for individual HTTP phases:

Child spanWhat it measures
dnsDNS lookup duration
tcp_connectTCP connection establishment
tls_handshakeTLS negotiation
ttfbTime from request sent to first response byte

No SDK config change is required. Android wires the OkHttp client factory with the Last9 interceptor and EventListener.Factory. iOS uses native URLProtocol/URLSession instrumentation and reads URLSession task metrics.

Reused connections skip DNS, TCP, and TLS work. For those requests the SDK emits zero-duration child spans with l9rum.network.phase.skipped=true so the waterfall shape stays consistent.

API reference

React Navigation integration

For automatic view tracking with React Navigation:

import { L9ReactNavigationInstrumentation } from '@last9/rum-react-native';
import { NavigationContainer } from '@react-navigation/native';
function App() {
return (
<NavigationContainer
onStateChange={L9ReactNavigationInstrumentation.onStateChange}
>
{/* screens */}
</NavigationContainer>
);
}

Identify a user

L9Rum.identify({
id: "user-123",
name: "Jane",
email: "jane@example.com",
fullName: "Jane Doe",
roles: ["admin"],
});

Clear user on sign-out

L9Rum.clearUser();

Capture errors

try {
// risky operation
} catch (error) {
L9Rum.captureError(error, { screen: "checkout" });
}

Track views manually

L9Rum.startView("ProductDetailsScreen");
L9Rum.setViewName("Product #42");

Custom events

L9Rum.addEvent("purchase_completed", {
product_id: "12345",
amount: 29.99,
});

Global span attributes

L9Rum.spanAttributes({
experiment: "checkout_v2",
feature_flag: "new_cart",
});
// Clear
L9Rum.spanAttributes(null);

Session ID

const sessionId = await L9Rum.getSessionId();

Flush pending data

L9Rum.flush();

WebView correlation

Instrument a react-native-webview WebView to share the native session ID with Browser RUM spans running inside it:

import { useRef } from 'react';
import { WebView } from 'react-native-webview';
import { L9Rum } from '@last9/rum-react-native';
const webViewRef = useRef<WebView>(null);
<WebView
ref={webViewRef}
source={{ uri: 'https://app.example.com' }}
onLoad={() => {
if (webViewRef.current) {
L9Rum.instrumentWebView(webViewRef);
}
}}
/>

The SDK resolves the underlying native WKWebView (iOS) or android.webkit.WebView (Android) and re-injects session context on every navigation automatically.

See the WebView Session Correlation guide for auto-load options and verification steps.

Next steps

Once data is flowing, explore it in Discover > Applications — performance, errors, and sessions.


Troubleshooting

Please get in touch with us on Discord or Email if you have any questions.