> ## Documentation Index
> Fetch the complete documentation index at: https://docs.newly.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Technical Details

> What gets added to your app — configuration keys, generated files, and important caveats

## Keys in app.json

After setup, the following keys are added to your `app.json` (under the `extra` field):

| Key                       | Example    | Description                             |
| ------------------------- | ---------- | --------------------------------------- |
| `revenueCatApiKeyIos`     | `appl_...` | Production iOS API key                  |
| `revenueCatApiKeyAndroid` | `goog_...` | Production Android API key              |
| `revenueCatTestApiKey`    | `test_...` | Test Store key for dev builds           |
| `revenueCatEntitlementId` | `pro`      | The entitlement to check (always "pro") |

The app automatically selects test keys in development (`__DEV__` is true) and production keys in release builds.

## Generated files

The AI agent creates or modifies these files:

| File                      | Purpose                                                                                                                                  |
| ------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
| `SubscriptionContext.tsx` | React context provider wrapping the RevenueCat SDK. Handles initialization, purchase state, and optionally syncs user ID if auth exists. |
| `/paywall` screen         | The paywall UI where users can subscribe. Shows pricing, features, and purchase buttons.                                                 |
| `_layout.tsx`             | Modified to wrap the app in `SubscriptionProvider` and add a `SubscriptionRedirect` for enforcing the paywall.                           |
| Onboarding integration    | If onboarding exists, the paywall is wired into the flow after onboarding completes.                                                     |

## Dependencies

The `react-native-purchases` package is installed automatically.

<Warning>
  **Do not add `react-native-purchases` to the `plugins` array in `app.json`.** This causes build errors. The SDK is configured entirely through `SubscriptionContext.tsx`, not as an Expo plugin.
</Warning>

## How API key switching works

The generated `SubscriptionContext.tsx` includes logic like:

```javascript theme={null}
const apiKey = __DEV__ && testApiKey ? testApiKey : platformApiKey;
```

* In development builds, the Test Store key is used so you can simulate purchases safely
* In production builds, the real iOS or Android key is used for actual App Store / Play Store purchases
* This switching is automatic — you don't need to change anything between environments

## Storage key scoping

To prevent conflicts between multiple apps that might share the same Expo slug, the subscription context uses your Newly project ID in its storage key. This ensures subscription state is isolated per-app.