Real User Monitoring

Last9 Real User Monitoring (RUM) captures real user experience data from web and mobile applications. Each SDK instruments sessions, views, network requests, unhandled errors, and resource metrics (plus ANRs on Android), then exports spans and logs to Last9 over OTLP/HTTP.

Supported platforms

Web JavaScript SDK. Core Web Vitals, JS errors, fetch/XHR instrumentation, session tracking. Works with React, Angular, Vue, Next.js.

Android Kotlin SDK. OkHttp interceptor, activity lifecycle, ANR detection, resource sampling.

iOS Swift SDK. URLProtocol instrumentation, UIKit/SwiftUI view tracking, crash capture.

React Native Bridges native Android + iOS SDKs. fetch/XHR instrumentation, React Navigation integration.

Flutter Dart plugin over native Android + iOS SDKs. HttpClient override, NavigatorObserver.

What gets captured

All SDKs auto-instrument the same signals:

Sessions — rolling session IDs with idle + max-duration expiry. Session ID is propagated on every span and log.
Views / page loads — screen transitions tracked as spans. Auto-tracked via SPA route changes (web), activity lifecycle (Android), UIKit/SwiftUI hooks (iOS), React Navigation (React Native), or NavigatorObserver (Flutter). Manual startView(name) is available on every platform.
Network — HTTP requests captured with URL, method, status, duration, request/response sizes. Traceparent header is injected so spans link to backend traces.
Errors — unhandled JS exceptions, promise rejections, native crashes, and Flutter framework errors. ANR detection is Android-only. Manual captureError(e, context) is available on every platform.
Core Web Vitals (web) — LCP, FCP, CLS, INP, TTFB.
Resources (mobile) — periodic memory and CPU samples (configurable interval, default 30s).
Custom events + attributes — addEvent, spanAttributes, and identify for user context.

Distribution

SDKs are distributed from Last9’s CDN:

Platform	Artifact	CDN root
Web	UMD script	`https://cdn.last9.io/rum-sdk/builds/stable/v2/l9.umd.js`
Android	Maven AAR	`https://cdn.last9.io/rum-sdk/android/maven/`
iOS	CocoaPods podspec + SPM XCFramework	`https://cdn.last9.io/rum-sdk/ios/builds/0.3.1/`
React Native	npm tarball	`https://cdn.last9.io/rum-sdk/react-native/builds/0.3.1/`
Flutter	tar.gz package	`https://cdn.last9.io/rum-sdk/flutter/builds/0.3.1/`

Mobile staging builds use the -alpha suffix.

Next steps

Pick your platform:

Once data is flowing, explore it in Discover > Applications — performance, errors, sessions, and session correlation with backend traces.

Troubleshooting

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