Install the iOS SDK

In Xcode, add the package https://github.com/useunion/union-ios from version 0.3.3 and link the Union library to your app target only — not to extensions or test targets. In a Package.swift:

There are no CocoaPods or Carthage variants.

Call configure exactly once, as early as possible — in your SwiftUI App initializer or at the top of application(_:didFinishLaunchingWithOptions:):

The write key is in Settings → SDK write keys. It is a client key, meant to ship inside your app, so it can be committed like any other app configuration. privacyMode must match the project’s setting in Union — .productAnalytics or .strictAnonymous (see Privacy).

configure already sends installs, updates, sessions, foreground and background, and device context. Do not send your own app_opened or session_started; they would duplicate what the panel already counts.

One key serves every build. The SDK detects the environment itself and sends it with every batch:

In SwiftUI, add .trackScreen("Name") to the root view of each screen. In UIKit, set options.automaticScreenTracking = true or call Union.screen("Name") in viewDidAppear. Screen names are stable and PascalCase ("Checkout", "WorkoutDetail") — never put data in a name, or every value becomes its own screen.

In product analytics mode, call Union.identify(userId:) after sign-in with your backend’s stable, opaque user id — never an email address — and Union.reset() on sign-out. Sessions before sign-in belong to the account the device signs in with. Strict anonymous projects skip this step entirely.

Names are lowercase snake_case, up to 64 characters, in the past tense (workout_finished). Up to 32 properties per event, each a string, number or bool, kept low-cardinality. An invalid event is logged and dropped; the SDK never throws. To group events into a funnel, declare a feature.

Run a DEBUG build in the simulator, then background the app (or wait ten seconds) so the batch is sent. Open Live in the Sandbox scope — the session appears within seconds.

/llms.txt is the whole integration as one prompt for Claude Code, Cursor or Codex. In the panel, Settings → SDK setup gives the same prompt filled in with your project’s key, privacy mode and integrations.