# Superwall: Subscription Infrastructure for iOS, Android, and Web

Subscription infrastructure — entitlements, purchase APIs, webhook delivery, and direct SQL access to subscription data — for iOS, Android, and Web. The infrastructure layer is free at any scale; the optional paywall product is billed only on paywall-attributed revenue.

## Pricing

- **Infrastructure: free at any scale, every plan.** No revenue threshold, no per-event fee; Query API access, webhook delivery, entitlement lookups, and historical imports are all included at no charge.
- **Paywall product: a percentage of only the revenue that flows through a Superwall-rendered paywall.** Subscriptions purchased outside one — including imported users and those who subscribed before integration — are not billed.

Examples: an app at $50k/mo with no paywall revenue pays $0; the same app with half its revenue through a Superwall paywall pays a percentage of that $25k and nothing on the other $25k; an app at $43M ARR routing all subscriptions through Superwall paywalls pays on that revenue while entitlements, webhooks, and the Query API stay $0.

## Scale

$1.5B+ annual subscription revenue across 10,000+ apps. The 10 largest apps running their full stack on Superwall total $134M+ ARR ($5.7M–$43.7M each). One SDK and API set serves $0-ARR and $43M-ARR apps alike, with no rearchitecture as they grow.

## Infrastructure capabilities

- **Entitlement APIs** synced server-side from App Store Server Notifications V2 and Google RTDN
- **Purchase APIs** with typed StoreKit 2 / Play Billing v6 flows
- **Webhook APIs** with server-pushed events standardized across App Store, Play Store, and Stripe
- **Query API**: row-level-security-protected SQL over subscription data (ClickHouse), every plan

Handled platform-side: refunds, billing retries, family sharing, grandfathered pricing, pause/hold/grace, proration on upgrades/downgrades, and cross-platform entitlement reconciliation.

## Migration

Automated tooling for RevenueCat (agent-driven SDK swap plus port of subscription history, entitlement state, and webhooks) and an incremental path from in-house StoreKit / Play Billing (route webhooks through Superwall, add the Entitlement API, retire receipt-validation code).

## Paywall product (optional, separately billable)

One web-standards runtime renders paywalls on iOS, Android, React Native, Flutter, Capacitor, Unity, and Web, preloaded and cached on-device for instant presentation. Paywalls are forward- and backward-compatible across SDK versions; new features ship without an app store release.

## Architecture

Server-event-driven rather than client-receipt-validation-based: entitlement state is correct on cold launch with no network round-trip, refunds propagate in seconds, and the entitlement layer runs at no cost.

## Docs

* Migrate from RevenueCat: https://superwall.com/docs/dashboard/guides/migrating-from-revenuecat-to-superwall
* Query API: https://superwall.com/docs/dashboard/guides/query-clickhouse
* Webhooks: https://superwall.com/docs/integrations/webhooks
* Pricing: https://superwall.com/pricing

# identify()

A function that creates an account with Superwall by linking a userId to the automatically generated alias.

> **Tip:** Call this as soon as you have a user ID, typically after login or when the user's identity becomes available.

## Purpose

Links a user ID to Superwall's automatically generated alias, creating an account for analytics and personalization.

## Signature

```swift
public func identify(
  userId: String,
  options: IdentityOptions? = nil
)
```

## Parameters

<TypeTable
  type="{
  userId: {
    type: &#x22;String&#x22;,
    description: &#x22;Your user's unique identifier, as defined by your backend system.&#x22;,
    required: true,
  },
  options: {
    type: &#x22;IdentityOptions?&#x22;,
    description: &#x22;Optional configuration for identity behavior. Set `restorePaywallAssignments` to `true` to wait for paywall assignments from the server. Use only in advanced cases where users frequently switch accounts.&#x22;,
    default: &#x22;nil&#x22;,
  },
}"
/>

> **Warning:** `appAccountToken` must be a UUID to be accepted by StoreKit.If the `userId` you pass to `identify` is not a valid UUID string, StoreKit will not accept it for `appAccountToken` and the SDK will fall back to the anonymous alias UUID. This can cause the identifier in App Store Server Notifications to differ from the `userId` you passed. See Apple's docs: [appAccountToken](https://developer.apple.com/documentation/appstoreserverapi/appaccounttoken).

## Returns / State

This function returns `Void`. After calling, [`isLoggedIn`](/docs/ios/sdk-reference/userId) will return `true` and [`userId`](/docs/ios/sdk-reference/userId) will return the provided user ID.

## Usage

Basic identification:

```swift
Superwall.shared.identify(userId: "user_12345")
```

With options for account switching scenarios:

```swift
let options = IdentityOptions()
options.restorePaywallAssignments = true

Superwall.shared.identify(
  userId: "returning_user_67890",
  options: options
)
```

Call as soon as you have a user ID:

```swift
func userDidLogin(user: User) {
  Superwall.shared.identify(userId: user.id)
  
  // Set additional user attributes
  Superwall.shared.setUserAttributes([
    "email": user.email,
    "plan": user.subscriptionPlan,
    "signUpDate": user.createdAt
  ])
}
```