iOS feature flags installation

  1. Install via CocoaPods

    Required

    Add PostHog to your Podfile:

    Podfile
    pod "PostHog", "~> 3.0"

    Or install via Swift Package Manager:

    Package.swift
    dependencies: [
      .package(url: "https://github.com/PostHog/posthog-ios.git", from: "3.0.0")
    ]

  2. Configure PostHog

    Required

    Initialize PostHog in your AppDelegate:

    AppDelegate.swift
    import Foundation
    import PostHog
    import UIKit
    

    class AppDelegate: NSObject, UIApplicationDelegate {
        func application(_: UIApplication, didFinishLaunchingWithOptions _: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
            let POSTHOG_API_KEY = "<ph_project_api_key>"
            let POSTHOG_HOST = "https://us.i.posthog.com"
    

            let config = PostHogConfig(apiKey: POSTHOG_API_KEY, host: POSTHOG_HOST)
            PostHogSDK.shared.setup(config)
    

            return true
        }
    }

  3. Send events

    Recommended

    Once installed, PostHog will automatically start capturing events. You can also manually send events to test your integration:

    Swift
    PostHogSDK.shared.capture("button_clicked", properties: ["button_name": "signup"])

    By default, for backwards compatibility reasons, events are sent with person profile processing enabled. This means a person profile will be created for each user who triggers an event.

    If you want to disable person profile processing for certain events, send the event with the following property:

    Swift
    "$process_person_profile": false

  4. Evaluate boolean feature flags

    Required

    Check if a feature flag is enabled:

    Swift
    let isMyFlagEnabled = PostHogSDK.shared.isFeatureEnabled("flag-key")
    if isMyFlagEnabled {
        // Do something differently for this user
        // Optional: fetch the payload
        let matchedFlagPayload = PostHogSDK.shared.getFeatureFlagPayload("flag-key")
    }

  5. Evaluate multivariate feature flags

    Optional

    For multivariate flags, check which variant the user has been assigned:

    Swift
    let enabledVariant = PostHogSDK.shared.getFeatureFlag("flag-key")
    if enabledVariant == "variant-key" { // replace 'variant-key' with the key of your variant
        // Do something differently for this user
        // Optional: fetch the payload
        let matchedFlagPayload = PostHogSDK.shared.getFeatureFlagPayload("flag-key")
    }

  6. Running experiments

    Optional

    Experiments run on top of our feature flags. Once you've implemented the flag in your code, you run an experiment by creating a new experiment in the PostHog dashboard.

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