Subscription Offers

This guide explains how to handle subscription offers (pricing plans) when purchasing subscriptions on iOS and Android platforms.

For a complete implementation example, see the Subscription Flow Example.

Overview

Subscription offers represent different pricing plans for the same subscription product:

• Base Plan: The standard pricing for a subscription
• Introductory Offers: Special pricing for new subscribers (free trial, discounted period)
• Promotional Offers: Limited-time discounts configured in the app stores

Platform Differences

At a glance:

• Android: subscription offers are required when purchasing subscriptions. You must pass subscriptionOffers with one or more offer tokens from fetchProducts().
• iOS: base plan is used by default. Promotional discounts are optional via withOffer.

Tip: Always fetch products first; offers only exist after fetchProducts({ type: 'subs' }).

Android Subscription Offers

Android requires explicit specification of subscription offers when purchasing. Each offer is identified by an offerToken obtained from fetchProducts().

Required for Android Subscriptions

Unlike iOS, Android subscriptions must include subscriptionOffers in the purchase request. Without it, the purchase will fail with:

The number of skus (1) must match: the number of offerTokens (0)

Getting Offer Tokens

import {useIAP} from 'expo-iap';

const SubscriptionComponent = () => {
  const {connected, subscriptions, fetchProducts, requestPurchase} = useIAP();

  // 1) Fetch subscription products
  useEffect(() => {
    if (connected) {
      fetchProducts({skus: ['premium_monthly'], type: 'subs'});
    }
  }, [connected]);

  // 2) Access offer details from fetched subscriptions
  const subscription = subscriptions.find((s) => s.id === 'premium_monthly');

  if (subscription?.subscriptionOfferDetailsAndroid) {
    console.log(
      'Available offers:',
      subscription.subscriptionOfferDetailsAndroid,
    );
    // Each offer contains: basePlanId, offerId?, offerTags, offerToken, pricingPhases
  }
};

Purchase with Offers

const purchaseSubscription = async (subscriptionId: string) => {
  const subscription = subscriptions.find((s) => s.id === subscriptionId);
  if (!subscription) return;

  // Build subscriptionOffers from fetched data
  const subscriptionOffers = (
    subscription.subscriptionOfferDetailsAndroid ?? []
  )
    .map((offer) =>
      offer?.offerToken
        ? {
            sku: subscriptionId,
            offerToken: offer.offerToken,
          }
        : null,
    )
    .filter((offer): offer is {sku: string; offerToken: string} =>
      Boolean(offer?.offerToken),
    );

  // Only proceed if offers are available
  if (subscriptionOffers.length === 0) {
    console.error('No subscription offers available');
    return;
  }

  await requestPurchase({
    request: {
      apple: {sku: subscriptionId},
      google: {
        skus: [subscriptionId],
        subscriptionOffers:
          subscriptionOffers.length > 0 ? subscriptionOffers : undefined,
      },
    },
    type: 'subs',
  });
};

Understanding Offer Details

Each subscriptionOfferDetailsAndroid item contains:

interface ProductSubscriptionAndroidOfferDetails {
  basePlanId: string; // Base plan identifier
  offerId?: string | null; // Offer identifier (null for base plan)
  offerTags: string[]; // Tags associated with the offer
  offerToken: string; // Token required for purchase
  pricingPhases: PricingPhasesAndroid; // Pricing information
}

Android basePlanId Limitation

The basePlanId is available when fetching products, but not when retrieving purchases via getAvailablePurchases(). This is a limitation of Google Play Billing Library - the purchase token alone doesn't reveal which base plan was purchased.

See GitHub Issue #3096 for more details. See the basePlanId Limitation section for details and workarounds.

iOS Subscription Offers

iOS handles subscription offers differently - the base plan is used by default, and promotional offers are optional.

Base Plan (Default)

For standard subscription purchases, no special offer specification is needed:

await requestPurchase({
  request: {
    apple: {sku: 'premium_monthly'},
    google: {
      skus: [
        'premium_monthly',
      ] /* include subscriptionOffers only if available */,
    },
  },
  type: 'subs',
});

Introductory Offers

iOS automatically applies introductory prices (free trials, intro pricing) configured in App Store Connect. No additional code is needed - users will see the introductory offer when eligible.

To check if a subscription has an introductory offer:

const subscription = subscriptions.find((s) => s.id === 'premium_monthly');

if (subscription?.subscriptionInfoIOS?.introductoryOffer) {
  const offer = subscription.subscriptionInfoIOS.introductoryOffer;

  switch (offer.paymentMode) {
    case 'free-trial':
      console.log(
        `${offer.periodCount} ${offer.period.unit.toLowerCase()}(s) free trial`,
      );
      break;
    case 'pay-as-you-go':
      console.log(
        `${offer.displayPrice} for ${
          offer.periodCount
        } ${offer.period.unit.toLowerCase()}(s)`,
      );
      break;
    case 'pay-up-front':
      console.log(
        `${offer.displayPrice} for first ${
          offer.periodCount
        } ${offer.period.unit.toLowerCase()}(s)`,
      );
      break;
  }
}

Promotional Offers (Optional)

iOS supports promotional offers through the withOffer parameter. These are server-to-server offers that require signature generation from your backend.

Getting Available Promotional Offers

const subscription = subscriptions.find((s) => s.id === 'premium_monthly');

if (subscription?.discountsIOS) {
  console.log('Available promotional offers:');
  subscription.discountsIOS.forEach((discount) => {
    console.log('- Identifier:', discount.identifier);
    console.log('  Price:', discount.localizedPrice);
    console.log('  Payment mode:', discount.paymentMode);
    console.log('  Subscription period:', discount.subscriptionPeriod);
    console.log('  Number of periods:', discount.numberOfPeriods);
  });
}

Applying Promotional Offers

To apply a promotional offer, you need to generate a signature on your backend server. See Apple's documentation for signature generation.

interface DiscountOfferInputIOS {
  identifier: string; // Offer identifier from discountsIOS
  keyIdentifier: string; // Your App Store Connect key ID
  nonce: string; // UUID generated on device
  signature: string; // Generated by your backend
  timestamp: number; // Unix timestamp in milliseconds
}

const purchaseWithPromotionalOffer = async (
  subscriptionId: string,
  offerId: string,
) => {
  // 1. Generate signature on your backend
  const nonce = generateUUID(); // Use a UUID library
  const timestamp = Date.now();

  const signature = await fetch('https://your-backend.com/generate-signature', {
    method: 'POST',
    body: JSON.stringify({
      productId: subscriptionId,
      offerId: offerId,
      applicationUsername: 'user-123', // Optional
      nonce: nonce,
      timestamp: timestamp,
    }),
  }).then((res) => res.json());

  // 2. Purchase with the promotional offer
  await requestPurchase({
    request: {
      apple: {
        sku: subscriptionId,
        withOffer: {
          identifier: offerId,
          keyIdentifier: signature.keyIdentifier,
          nonce: nonce,
          signature: signature.signature,
          timestamp: timestamp,
        },
      },
      google: {skus: [subscriptionId], subscriptionOffers: [...]},
    },
    type: 'subs',
  });
};

Common Patterns

Selecting Specific Offers

const selectOffer = (
  subscription: ProductSubscription,
  offerType: 'base' | 'introductory',
) => {
  if (Platform.OS === 'ios') {
    // iOS: Check for introductory offer
    if (offerType === 'introductory') {
      return subscription.subscriptionInfoIOS?.introductoryOffer ?? null;
    }
    // Base plan is default, no selection needed
    return null;
  }

  // Android: Select offer based on type
  const offers = subscription.subscriptionOfferDetailsAndroid ?? [];

  if (offerType === 'base') {
    // Find base plan (no offerId)
    return offers.find((offer) => !offer.offerId);
  } else {
    // Find introductory offer
    return offers.find((offer) => offer.offerId?.includes('introductory'));
  }
};

const purchaseWithSelectedOffer = async (
  subscriptionId: string,
  offerType: 'base' | 'introductory' = 'base',
) => {
  const subscription = subscriptions.find((s) => s.id === subscriptionId);
  if (!subscription) return;

  const selectedOffer = selectOffer(subscription, offerType);

  if (Platform.OS === 'android') {
    const subscriptionOffers = selectedOffer
      ? [
          {
            sku: subscriptionId,
            offerToken: selectedOffer.offerToken,
          },
        ]
      : [];

    if (subscriptionOffers.length === 0) {
      console.error('No suitable offer found');
      return;
    }

    await requestPurchase({
      request: {
        apple: {sku: subscriptionId},
        google: {
          skus: [subscriptionId],
          subscriptionOffers:
            subscriptionOffers.length > 0 ? subscriptionOffers : undefined,
        },
      },
      type: 'subs',
    });
  } else {
    // iOS: Introductory offers are automatically applied
    // selectedOffer contains intro price info for display purposes
    if (offerType === 'introductory' && selectedOffer) {
      console.log('Offer:', selectedOffer.displayPrice);
      console.log('Payment mode:', selectedOffer.paymentMode);
    }

    await requestPurchase({
      request: {
        apple: {sku: subscriptionId},
        google: {
          skus: [
            subscriptionId,
          ] /* include subscriptionOffers only if available */,
        },
      },
      type: 'subs',
    });
  }
};

Error Handling

Android Errors

import {useIAP, ErrorCode} from 'expo-iap';

const {requestPurchase} = useIAP({
  onPurchaseError: (error) => {
    if (error.code === ErrorCode.PurchaseError) {
      console.error('Purchase failed - check subscription offers');
      // Ensure subscriptionOffers is included and valid
    }
  },
});

iOS Errors

import {useIAP, ErrorCode} from 'expo-iap';

const {requestPurchase} = useIAP({
  onPurchaseError: (error) => {
    if (error.code === ErrorCode.Unknown) {
      console.error('Invalid promotional offer for iOS');
      // Check offerIdentifier, signature, etc.
    }
  },
});

Best Practices

1. Always fetch products first: Subscription offers are only available after fetchProducts().

2. Handle platform differences: Android requires offers, iOS makes them optional.

3. Validate offers: Check that offers exist before attempting purchase.

4. User selection: Allow users to choose between different pricing plans when multiple offers are available.

5. Error recovery: Provide fallback to base plan if selected offer fails.

See Also

• useIAP Hook - Main API documentation
• Subscription Flow Example - Complete implementation
• Error Codes - Purchase error handling