# 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

# setIntegrationAttribute()

Sets a single attribute for third-party integrations.

## Purpose

Syncs a user identifier from an analytics or attribution provider with Superwall. This enables better user tracking and attribution across platforms.

## Signature

```dart
Future<void> setIntegrationAttribute(
  IntegrationAttribute attribute,
  String? value,
)
```

## Parameters

<TypeTable
  type="{
  attribute: {
    type: &#x22;IntegrationAttribute&#x22;,
    description: &#x22;The integration attribute key specifying the integration provider.&#x22;,
    required: true,
  },
  value: {
    type: &#x22;String?&#x22;,
    description: &#x22;The value to associate with the attribute. Pass `null` to remove the attribute.&#x22;,
  },
}"
/>

## Returns / State

Returns a `Future<void>` that completes when the attribute is set.

## Usage

Setting an integration attribute:

```dart
await Superwall.shared.setIntegrationAttribute(
  IntegrationAttribute.mixpanelDistinctId,
  'user_123',
);
```

Removing an integration attribute:

```dart
await Superwall.shared.setIntegrationAttribute(
  IntegrationAttribute.mixpanelDistinctId,
  null,
);
```

Syncing with multiple providers:

```dart
// Mixpanel
await Superwall.shared.setIntegrationAttribute(
  IntegrationAttribute.mixpanelDistinctId,
  mixpanelUserId,
);

// Amplitude
await Superwall.shared.setIntegrationAttribute(
  IntegrationAttribute.amplitudeUserId,
  amplitudeUserId,
);

// Adjust
await Superwall.shared.setIntegrationAttribute(
  IntegrationAttribute.adjustId,
  adjustId,
);
```

## Related

* [`setIntegrationAttributes()`](/docs/flutter/sdk-reference/setIntegrationAttributes) - Set multiple attributes at once
* [`IntegrationAttribute`](/docs/flutter/sdk-reference/IntegrationAttribute) - Available integration attribute types