InAppPurchaseKit Module Overview

Powered by RevenueCat (Official Partner of SwiftyLaunch)

InAppPurchaseKit wraps RevenueCat's SDK to allow for an even easier integration of paywalls and in-app purchases in your app.

After generating a project with InAppPurchaseKit enabled and completing the initial project setup, you will get following features out of the box:

• A customizable pre-built paywall: A paywall view that allows you to easily customize it to your liking. Read more.
• Ability to lock actions behind a paywall: Lock features behind a paywall and show the paywall when the user tries to access them. Read more.
• Ability to lock views behind a paywall: Lock views behind a paywall and show the paywall when the user tries to access them. Read more.
• An entry in the app settings screen: A dedicated view in the app settings screen to manage subscriptions and purchases. Read more.
• (AnalyticsKit only) Automatic analytics tracking: Automatically track events related to paywalls and purchases. Read more.
• (AuthKit only) Ability to use a shared user ID: If the user is signed in, the Firebase user ID is used as the alias ID for RevenueCat. Read more.
• (BackendKit only) BackendKit integration: You can also access InAppPurchaseKit information on the backend. Read more.

Module Deep Dive

Initialization and Configuration

1. We initilize InAppPurchaseKit in App.swift: by calling a static function InAppPurchases.initRevenueCat()
2. Only when generated with AuthKit: We observe if the user has signed into an account, and use the Firebase user ID as the alias ID for RevenueCat, so the user can be accurately tracked across different providers via InAppPurchases.associateUserWithID(USER_ID). We remove that alias when the user signes out by calling InAppPurchases.removeUserIDAssociation().

General Usage

The InAppPurchases object was designed to be used as an EnvironmentObject throughout the application and is attached to the root of the view hierarchy in App.swift. By default, we use the abbreviation iap for the environment object.

Here are some of the relevant InAppPurchases object parameters and functions that you can access:

Access Subscription State

@Published public private(set) var subscriptionState: SubscriptionState = .notSubscribed

Can either be .notSubscribed or .subscribed. Updated automatically by the listenForSubscriptionStateChange() listener that is called during initialization.

Show Paywall Sheet

static public func showPaywallSheet() { }

A static InAppPurchases function that will show the paywall sheet. The function sends a notification to the notification center while the view modifier placed in App.swift called ShowPaywallSheetWhenCalledModifier() listens to that notification and presents the paywall sheet.

Execute if User is Subscribed

public func executeIfGotPremium(otherwise consequence: NoPremiumConsequence = .showPaywall, _ closure: () -> Void) { }

A function that that executes the provided closure if the user is subscribed. If the user is not subscribed, the consequence parameter will determine what happens next. (Will either show the paywall or show an in-app notification saying that the feature required premium). Read more in the Lock Actions behind Paywall section.

Show System Subscription Management Screen

static public func showSubscriptionManagementScreen() async {}

A static InAppPurchases function that opens the system subscription management screen. Is shown on the InAppPurchases Settings Screen (when the user taps on "Manage Subscription").

Show View if User is Subscribed

public func requirePremium(iap: InAppPurchases, onCancel: @escaping () -> Void) -> some View {}

A view modifier that allows you to lock views behind the paywall. If the user is subscribed, the view will be shown as usual, otherwise the paywall will be shown. Read more in the Lock Views behind Paywall section.

AuthKit Integration

If AuthKit is selected during project generation, your app will automatically add Firebase User ID as an alias to the RevenueCat user ID when the user signes in. This allows you to access user information on the dashboard or on the backend (using BackendKit) by simply using the Firebase User ID.

AnalyticsKit Integration

If AnalyticsKit is selected during project generation, most of the events related to paywalls and purchases are automatically tracked with iap as the source.

An example entry in the PostHog dashboard:

Module File Contents

Let's go through every file that is contained in the InAppPurchaseKit module:

Config

Contains the RevenueCat-Info.plist file that you will paste your RevenueCat API key into.

Resources

Contains the hero video placeholder that is shown by default on the first page in the carousel of the paywall

Sources

Model / InAppPurchases.swift

Contains the InAppPurchases observable class, which is the entry point to interact with the module.

ViewModifier / requirePremium.swift

Exposes the .requirePremium() view modifier that allows you to lock views behind the paywall. See Lock Views behind Paywall for more information.

ViewModifier / ShowPaywallSheetWhenCalledModifier.swift

Exposes the ShowPaywallSheetWhenCalledModifier() view modifier that listens for the showPaywallSheet() notification and presents the paywall sheet. Because we only use it in the root view in App.swift, we don't wrap it around a more general view modifier, and attach it via .modifier(ShowPaywallSheetWhenCalledModifier()).

Additionally, extends the InAppPurchases class with the showPaywallSheet() function that sends the notification.

View / InAppPurchaseView.swift

The paywall view that is shown when the user tries to access a feature that requires premium. You can customize this view to your liking, see Paywall for more information.

View / PremiumSettingsView.swift

View that can contains premium-related settings in the app. By default shows the "Manage Subscription" button that opens the system subscription management screen. See Premium Settings Screen for more information.