iOS / Swift
Install and configure the Last9 iOS RUM SDK. Swift API, CDN-hosted CocoaPods podspec and SPM XCFramework, automatic instrumentation for sessions, views, network, errors, and resource sampling.
Real User Monitoring for iOS apps. Automatic instrumentation for sessions, views, network requests, errors, and resource metrics via OpenTelemetry.
Prerequisites
- iOS 15.1+
- Swift 5.9+
- Dependencies (resolved transitively):
OpenTelemetry-Swift-Api ~> 1.10,OpenTelemetry-Swift-Sdk ~> 1.10 - A Last9 RUM client token and OTLP endpoint
Create a Client Monitoring Token
- Open Last9 → Settings → Ingestion Tokens
- Click Create Token → choose type Client
- Set the allowed origin to
ios://com.yourcompany.yourapp— use your app’s exact bundle ID - Copy the token and the OTLP endpoint URL
CDN artifacts
| Artifact | URL |
|---|---|
| Podspec | https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.podspec |
| XCFramework | https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.xcframework.zip |
| Checksum | https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.xcframework.zip.sha256 |
Staging builds use the -alpha suffix.
Installation
-
Add to your
Podfilepod 'Last9RUM', :podspec => 'https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.podspec' -
Install
pod install
-
Fetch the checksum
curl -sL https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.xcframework.zip.sha256 -
Add a binary target to
Package.swift.binaryTarget(name: "Last9RUM",url: "https://cdn.last9.io/rum-sdk/ios/builds/0.7.0/Last9RUM.xcframework.zip",checksum: "<sha256 from previous step>")
Initialization
import Last9RUM
@mainclass AppDelegate: UIResponder, UIApplicationDelegate { func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool {
var config = L9RumConfig( baseUrl: "https://otlp-ext-aps1.last9.io/v1/otlp/organizations/<org>", clientToken: "your-client-token", serviceName: "my-ios-app", serviceVersion: "1.0.0", deploymentEnvironment: "production" ) // Use your app's bundle ID in ios:// format — must match the origin // allowlist on your Last9 client token. config.origin = "ios://com.example.myapp"
L9Rum.shared.initialize(config: config) return true }}import Last9RUMimport SwiftUI
@mainstruct MyApp: App { init() { var config = L9RumConfig( baseUrl: "https://otlp-ext-aps1.last9.io/v1/otlp/organizations/<org>", clientToken: "your-client-token", serviceName: "my-ios-app", serviceVersion: "1.0.0", deploymentEnvironment: "production" ) config.origin = "ios://com.example.myapp" L9Rum.shared.initialize(config: config) }
var body: some Scene { WindowGroup { ContentView() } }}What’s captured automatically
| Signal | Details |
|---|---|
| Network requests | Every URLSession call — latency, status code, URL |
| Screen views (UIKit) | UIViewController lifecycle callbacks |
| Screen views (SwiftUI) | .trackView(name:) modifier |
| Sessions | 15m inactivity / 4h max, persisted across restarts |
| App launch time | Cold and warm start duration |
| Resource metrics | Memory and CPU sampled periodically |
| Errors | Unhandled exceptions and crashes |
| ANR detection | Main thread blocks beyond threshold |
view.ttfd | Time from last HTTP response to next rendered frame — measures post-API render latency on data-driven screens |
View time-to-full-display (view.ttfd)
view.ttfd measures how long it takes for the screen to render after the last API response completes. It captures the delta between the HTTP response timestamp and the next CADisplayLink callback — giving you end-to-end visibility on data-driven screens where content appears only after a network call.
| Attribute | Type | Description |
|---|---|---|
view.ttfd | float | Milliseconds between HTTP response end and next rendered frame |
view.ttid | float | Milliseconds from screen open to first frame (unchanged) |
How it works: after any L9URLProtocol response callback fires, the SDK schedules a CADisplayLink on the main run loop. On the next display frame, the delta is recorded as view.ttfd on the active View span.
- Works on both SwiftUI and UIKit with no app code changes.
- Applies to the View span that was active when the HTTP call was made.
- If no View span is active when the response arrives, the measurement is skipped.
Configuration
var config = L9RumConfig( // --- Required --------------------------------------------------------- baseUrl: "https://otlp-ext-aps1.last9.io/v1/otlp/organizations/<org>", clientToken: "your-client-token", serviceName: "my-ios-app", serviceVersion: "1.0.0", deploymentEnvironment: "production")
// --- Optional -------------------------------------------------------------
// Origin sent as X-LAST9-ORIGIN header.// Required for client_monitoring tokens. Use ios://com.your.bundle.id —// must match the origin allowlist configured on your Last9 client token.config.origin = "ios://com.example.myapp"
// Specific build identifier (maps to app.build_id)config.appBuildId = "1.0.0-build-42"
// Unique per-install ID (NOT a hardware ID). Persists across launches.config.appInstallationId = nil
// Session sampling rate: 0-100 (percentage). 100 = sample everything.config.sampleRate = 100
// Print debug logs to consoleconfig.debugLogs = false
// Automatically trace HTTP requests via URLProtocolconfig.networkInstrumentation = true
// Automatically capture unhandled exceptionsconfig.errorInstrumentation = true
// Max spans per export batchconfig.maxExportBatchSize = 100
// Export timeout in millisecondsconfig.exportTimeoutMs = 30_000
// Periodically sample memory and CPUconfig.resourceMonitoringEnabled = true
// Interval between resource samples (ms)config.resourceSamplingIntervalMs = 30_000
// 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.config.isolateTracePerRequest = false
// Custom resource attributes added to every spanconfig.resourceAttributes = [ "app.platform": "ios",]
// W3C Baggage propagation on outgoing requestsconfig.baggage = L9BaggageConfig()config.baggage.enabled = falseconfig.baggage.allowedKeys = ["session.id", "user.id"]config.baggage.maxTotalBytes = 8192config.baggage.trackedUrlPatterns = []config.baggage.warnAtPercentage = 80
// Substring patterns — matching URLs are skipped before span creation.// Prefer ignorePatterns below for regex support and hostname/pathname targeting.config.excludedUrlPatterns = [".jpg", ".png", ".pdf", "cdn.example.com"]
// Fine-grained network ignore rules. Matched URLs are dropped before span// creation. .contains uses substring matching; .regex uses regex search semantics.// Takes precedence over excludedUrlPatterns.config.ignorePatterns = L9NetworkIgnorePatterns( fullUrl: [ .contains("https://cdn.example.com"), .regex("^https://.*\\.example\\.com", options: [.caseInsensitive]), ], pathname: [ .contains(".pdf"), .contains(".jpg"), .regex("^/internal/metrics"), ], hostname: [ .contains("cdn.example.com"), .regex("(^|\\.)assets\\.example\\.com$", options: [.caseInsensitive]), ])
// Trace header propagation for ignored URLs.// .preserve (default): keep traceparent on ignored requests.// .strip: remove traceparent from ignored requests (e.g. third-party CDNs).config.propagationMode = .preserveNetwork phase child spans
When URLSession instrumentation is enabled, each parent HTTP span includes child spans for individual network phases:
| Child span | What it measures |
|---|---|
dns | DNS lookup duration |
tcp_connect | TCP connection establishment |
tls_handshake | TLS negotiation |
ttfb | Time from request sent to first response byte |
No SDK config change is required. The SDK reads URLSessionTaskMetrics.transactionMetrics from the URLSession task delegate and emits phase child spans under the parent HTTP span automatically.
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
Identify a user
L9Rum.shared.identify(userId: "user-123", attributes: [ "email": "user@example.com", "plan": "premium",])Clear user on sign-out
L9Rum.shared.clearUser()Capture errors
do { try riskyOperation()} catch { L9Rum.shared.captureError(error, context: ["screen": "checkout"])}Track views (SwiftUI / Custom Navigation)
UIKit views are tracked automatically. For SwiftUI or custom navigation:
L9Rum.shared.startView("ProductDetailsScreen")L9Rum.shared.setViewName("Product #42")Custom events
L9Rum.shared.addEvent("purchase_completed", attributes: [ "product_id": "12345", "amount": 29.99,])Global span attributes
// Inject attributes into every spanL9Rum.shared.spanAttributes([ "experiment": "checkout_v2", "feature_flag": "new_cart",])
// ClearL9Rum.shared.spanAttributes(nil)Session ID
let sessionId: String? = L9Rum.shared.getSessionId()Flush pending data
L9Rum.shared.flush()Network ignore patterns
Skip noisy URLs before span creation by matching against full URL, pathname, or hostname. .contains uses substring matching; .regex uses regex search semantics.
config.ignorePatterns = L9NetworkIgnorePatterns( fullUrl: [ .contains("https://cdn.example.com"), .regex("^https://.*\\.example\\.com", options: [.caseInsensitive]), ], pathname: [ .contains(".pdf"), .contains(".jpg"), .regex("^/internal/metrics"), ], hostname: [ .contains("cdn.example.com"), .regex("(^|\\.)assets\\.example\\.com$", options: [.caseInsensitive]), ])// PRESERVE (default): keep traceparent on ignored requests.// STRIP: remove traceparent from ignored requests.config.propagationMode = .preserveWebView correlation
Inject the active native session and view IDs into a WKWebView so Browser RUM spans share the same session.id:
// After creating the WKWebView — call once per WKWebView instance.L9Rum.shared.instrument(webView: webView)- Session and view IDs are re-injected on every navigation commit and view change.
- Cross-origin iframes do not receive the session ID.
- Calling
instrument(webView:)beforeinitialize(config:)emits a warning and is a no-op.
Requires the Browser RUM JS SDK on the page. The JS SDK adopts the native session ID and fires l9rum:session_rollover when the session rotates, rotating the view span accordingly.
See the WebView Session Correlation guide for React Native/Flutter setup, the static-script path, auto-load Browser RUM, and verification steps.
Security
Client monitoring tokens are write-only and origin-scoped to your app’s bundle ID. Safe to ship in the app binary.
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.