Setting Up App Store In-App Purchase Event Notifications: A Complete Guide

Kadir Melih Can — Sun, 29 Dec 2024 14:11:11 +0000

Are you an iOS developer looking for a simple way to monitor your app's in-app purchases and subscriptions? In this guide, I'll show you how to set up a notification system that sends real-time App Store purchase events directly to your Discord, Slack and Telegram channels. Perfect for indie developers and small teams!

🚀 Get Started Quickly: Check out the GitHub repository for ready-to-deploy code and detailed setup instructions.

The repository includes:

Serverless function code for both Google Cloud Functions and Cloudflare Workers
Configuration templates for Discord, Telegram, and Slack
Example notification payloads and testing scripts
Comprehensive documentation and troubleshooting guides

Table of Contents 📑

What We'll Build 🛠️
Setting Up Your Notification Channel 📢
- Discord Setup
- Telegram Setup
Setting Up and Deploying to Google Cloud Function ☁️
Setting Up and Deploying to Cloudflare Workers ⚡️
Connecting to App Store Connect 🔗
- Using Adapty
- Using RevenueCat
- Direct Setup
What You'll Get 📱
- Example Notifications
Advanced Features 🔧
- Customizing Notifications
- Error Handling
- Timezone Support
Troubleshooting 🔍
Platform Comparison 🤔
Cost Considerations 💰
- Free Tier Comparison
- Cost Examples
- Optimization Tips
Security Best Practices 🔒
Technical Details and Examples 🔧
- Example App Store Notification
- Understanding the Notification Fields
- Processing Best Practices
Testing with cURL Examples 🧪
What's Next 🚀
Need Help 🤝

What We'll Build 🛠️

We'll create a serverless function that:

Receives App Store Server-to-Server notifications
Processes the purchase events
Sends beautifully formatted notifications to your preferred platform

Setting Up Your Notification Channel 📢

For Discord:

1. Open your Discord server

Launch Discord and open the server where you want to create the webhook.

2. Create a new Channel

If you don't have a channel already, create one by clicking on the "+" sign next to your server’s channel list.

3. Access Channel Settings

Hover over the channel you want to create a webhook for. Click the gear icon (⚙️) to open Channel Settings.

4. Go to Integrations

In the left sidebar, scroll down and click on Integrations. Under the "Integrations" section, click on Create Webhook.

5. Configure Your Webhook

Name your webhook and customize its settings if needed. Afterward, click Copy Webhook URL to save the URL for later use.

For Telegram:

1. Message @BotFather on Telegram

Open Telegram and search for @botfather. This is the official bot used to create and manage bots on Telegram.

2. Create a new bot with /newbot

Start a chat with @botfather and type /newbot to begin the process of creating a new bot.

3. Copy your bot token

After creating your bot, you’ll receive a token. Copy the token by clicking on the red highlighted area in the message from BotFather.

4. Create a channel and add your bot as an admin

If you don’t already have a Telegram channel, create one by going to the Telegram app and selecting New Channel. Once the channel is created, add your bot as an admin so it can send and receive messages.

5. Get your channel ID

Send a message to your channel first. Then forward that message to
@userinfobot

Write userinfobot in search, select the bot and forward the message.

Check message that UserInfoBot's sent you. (Eg. Your chat id: "-1002328487593")

Setting Up and Deploying to Google Cloud Function ☁️

Visit Google Cloud Console
Create a new project or select an existing one
Go to Cloud Run Functions
Click "Create Function"

If you did not enable required APIs previously, you will see this modal. You should click Enable button. After enabled APIs, you will be redirected the creating new function page.

Enter a name (1), choose HTTPS (2), select Allow unauthenticated invocations (3)

After you created function you will see the Code Editor
You will have 2 files: index.js and package.json
Copy the following code into package.json:

{
  "name": "iap-notifications",
  "version": "1.0.0",
  "description": "App Store server-to-server (S2S) notifications handler for in-app purchases",
  "main": "index.js",
  "dependencies": {
    "@google-cloud/functions-framework": "^3.4.4",
    "axios": "^1.7.9",
    "base64url": "^3.0.1",
    "country-iso-3-to-2": "^1.1.1",
    "date-fns-tz": "^3.2.0",
    "jsonwebtoken": "^9.0.2"
  },
  "scripts": {
    "start": "functions-framework --target=main --port=8080",
    "deploy:gcf": "gcloud functions deploy iap-notifications --gen2 --runtime=nodejs20 --region=us-central1 --memory=256MB --timeout=60s --min-instances=0 --max-instances=10 --trigger-http --allow-unauthenticated",
    "deploy:cf": "wrangler deploy"
  },
  "keywords": [
    "app-store",
    "server-to-server",
    "notifications",
    "telegram-bot",
    "discord-webhook",
    "slack-webhook"
  ],
  "author": "Kadir Melih Can",
  "license": "MIT",
  "engines": {
    "node": ">=20.0.0"
  }
}

Copy the source code into index.js and configure your notification settings:

const CONFIG = {
  general: {
    allowSandboxNotifications: true,
    timezone: "Europe/Istanbul",
    dateFormat: "dd.MM.yyyy HH:mm:ss"
  },
  telegram: {
    enabled: true,
    botToken: "YOUR_BOT_TOKEN",
    chatId: "YOUR_CHAT_ID"
  },
  discord: {
    enabled: true,
    webhookUrl: "YOUR_DISCORD_WEBHOOK_URL"
  },
  slack: {
    enabled: true,
    webhookUrl: "YOUR_SLACK_WEBHOOK_URL",
    channel: "#app-store-notifications"
  }
};

Do not forget to change Entry point field's value as main as in screenshot.

Click "Deploy" and wait for the deployment to complete
Copy your function's URL from the "Trigger" tab

Setting Up and Deploying to Cloudflare Workers ⚡️

1. Create a Cloudflare Account:

Visit Cloudflare Dashboard
Sign up for a free account if you don't have one
Verify your email address

2. Create a New Worker:

Click on "Workers & Pages" in the left sidebar
Click "Create" button
Select "Create Worker"
Choose a name for your worker and deploy (e.g., "iap-notifications")
After deployed successfully click the "Edit Code" button
Paste code in worker.js file into the code editor.

3. Save and Deploy:

Click "Save and deploy"
Wait for deployment to complete
Copy your worker's URL (format: https://iap-notifications.your-username.workers.dev)

Connecting to App Store Connect 🔗

Using Adapty:

Log in to Adapty
Navigate to App settings > Apps in the Adapty dashboard
Click to the iOS SDK section, scroll to App Store server notifications
Enter your the Cloud Function or CloudFlare Worker's URL to URL for forwarding raw Apple events
Click Save in the bottom left corner.

Using RevenueCat:

Log in to RevenueCat
Navigate to your iOS app under Project settings > Apps in the RevenueCat dashboard
Scroll to the Apple Server to Server notification settings section, and enter your the Cloud Function or CloudFlare Worker URL in Apple Server Notification Forwarding URL
Click Save Changes in the top right corner.

Direct App Store Connect Setup:

If you are using an internal solution, your own backend url is probably added here. Therefore, you can prepare an endpoint for your own backend and give it to the Google Cloud function or CloudFlare worker we prepared as the raw event arrives.

Open App Store Connect
Select your app
Go to App Information
Scroll to "App Store Server Notifications"
Enter your Cloud Function or CloudFlare URL
Save changes

What You'll Get 📱

Once set up, you'll receive beautifully formatted notifications for events like:

New purchases
Subscription renewals
Refunds
Consumption requests
Billing issues

Example Notifications by Platform

Telegram Notification

MyApp.bundle.id
🔔 DID_RENEW $99.99 💵

📊 Event: AUTO_RENEW_ENABLED
🏷 Product: premium_yearly
🌍 Country: 🇺🇸 USA
💰 Price: 99.99 USD

ℹ️ Additional Info:
• Environment: Production
• ID: 2000000000000000
• Type: Auto-Renewable Subscription
• Expires Date: 15.03.2025 14:30:00

Discord Notification

Discord notifications use rich embeds with:

Color-coded status
App Store icon thumbnail
Clickable app link
Organized fields for event details
Footer with transaction details

Advanced Features 🔧

Customizing Notifications

You can customize the notification format by modifying the respective service classes in index.js:

TelegramNotification for Telegram
DiscordNotification for Discord
SlackNotification for Slack

Error Handling

The system includes:

Automatic retries for failed API calls
Rate limiting protection
Sandbox environment filtering
Detailed error logging

Timezone Support

Configure your preferred timezone in the CONFIG object:

general: {
  timezone: "Your/Timezone",
  dateFormat: "dd.MM.yyyy HH:mm:ss"
}

Common Timezone Examples:

// United States
timezone: "America/New_York"     // Eastern Time
timezone: "America/Chicago"      // Central Time
timezone: "America/Denver"       // Mountain Time
timezone: "America/Los_Angeles"  // Pacific Time

// Europe
timezone: "Europe/London"        // British Time
timezone: "Europe/Paris"         // Central European Time
timezone: "Europe/Istanbul"      // Turkish Time

// Asia
timezone: "Asia/Dubai"          // Gulf Time
timezone: "Asia/Singapore"      // Singapore Time
timezone: "Asia/Tokyo"          // Japan Time

// Australia
timezone: "Australia/Sydney"    // Australian Eastern Time

Date Format Examples:

// Common Formats
dateFormat: "dd.MM.yyyy HH:mm:ss"    // 31.12.2024 14:30:00
dateFormat: "MM/dd/yyyy hh:mm:ss a"  // 12/31/2024 02:30:00 PM
dateFormat: "yyyy-MM-dd HH:mm:ss"    // 2024-12-31 14:30:00
dateFormat: "dd MMM yyyy HH:mm"      // 31 Dec 2024 14:30

// Format Tokens
// dd    - Day of month (01-31)
// MM    - Month (01-12)
// yyyy  - Full year
// HH    - Hours in 24h format (00-23)
// hh    - Hours in 12h format (01-12)
// mm    - Minutes (00-59)
// ss    - Seconds (00-59)
// a     - AM/PM marker

Troubleshooting 🔍

No notifications received:
- Check if your webhook URLs are correct
- Verify your Cloud Function is deployed and accessible
- Ensure the correct URL is set in App Store Connect
Webhook errors:
- Verify your bot/webhook permissions
- Check if the channel/chat IDs are correct
- Ensure your notification service is enabled in CONFIG
Invalid timestamps:
- Update the timezone in CONFIG to match your location
- Verify the dateFormat string is correct

Comparison of Google Cloud Functions vs Cloudflare Workers: Free vs Paid Tiers 🤔

Which One Should You Choose?

Choose Google Cloud Functions if you:

Need more free tier requests
Want deeper integration with other Google services
Require more computing resources
Need detailed logging and monitoring

Choose Cloudflare Workers if you:

Want global edge deployment
Need better cold start performance
Prefer simpler deployment process
Want built-in DDoS protection

Both platforms are excellent choices for this project. For most indie developers, either option will work great as both offer generous free tiers and reliable performance.

Cost Considerations 💰

Google Cloud Functions Free Tier

2 million invocations per month
400,000 GB-seconds of compute time
200,000 GHz-seconds of compute time
5GB network egress per month
No credit card required to start

Paid Tier (if you exceed free tier):

$0.40 per million invocations
$0.0000025 per GB-second
$0.0000100 per GHz-second

Cloudflare Workers Free Tier

100,000 requests per day (~3 million/month)
Unlimited scripts/workers
128MB memory limit per worker
10ms CPU time per request
Workers KV: 100,000 reads per day
Global edge deployment included

Paid Tier (Workers Paid Plan):

$5/month for 10 million requests
Increased CPU limits (50ms)
1GB memory limit per worker
Workers KV: 1 million reads per day

Cost Estimation Examples

For a typical indie app (5,000 monthly active users):

Average 1-2 events per user per month
Total: ~10,000 events/month
Easily covered by both platforms' free tiers

For a growing app (50,000 monthly active users):

Average 1-2 events per user per month
Total: ~100,000 events/month
Google Cloud Functions: Still within free tier
Cloudflare Workers: May need paid plan depending on daily distribution

For a large app (500,000 monthly active users):

Average 1-2 events per user per month
Total: ~1,000,000 events/month
Google Cloud Functions:
- Still within free tier
- Minimal cost if exceeded (~$0.40)
Cloudflare Workers:
- Paid plan recommended ($5/month)
- Better global performance

Cost Optimization Tips

Monitor Usage
- Set up billing alerts
- Track daily/monthly usage
- Monitor error rates
Reduce Costs
- Filter unnecessary notifications
- Batch events when possible
- Optimize code execution time
Choose the Right Plan
- Start with free tier
- Upgrade only when needed
- Consider your app's growth rate

Both platforms offer excellent value for money, especially for indie developers and small teams. The free tiers are typically sufficient for apps with up to 100,000 monthly active users, making them perfect for getting started and scaling up.

Security Best Practices 🔒

Keep your webhook URLs private
Enable Cloud Function authentication if needed
Regularly rotate webhook URLs
Monitor function logs for unusual activity
Set up billing alerts in Google Cloud

Technical Details and Examples 🔧

Example App Store Notification

Here's an example of the raw JSON data you'll receive from Apple (with randomized sensitive information):

{
  "data": {
    "appAppleId": 9876543210,
    "bundleId": "com.example.myapp",
    "bundleVersion": "4",
    "environment": "Production",
    "renewalInfo": {
      "autoRenewProductId": "myapp_premium_annual",
      "autoRenewStatus": 1,
      "currency": "USD",
      "environment": "Production",
      "originalTransactionId": "200001234567890",
      "productId": "myapp_premium_annual",
      "recentSubscriptionStartDate": 1729488392000,
      "renewalDate": 1761283592000,
      "renewalPrice": 99990,
      "signedDate": 1735414243588
    },
    "transactionInfo": {
      "bundleId": "com.example.myapp",
      "currency": "USD",
      "environment": "Production",
      "expiresDate": 1761283592000,
      "inAppOwnershipType": "PURCHASED",
      "originalTransactionId": "200001234567890",
      "price": 99990,
      "productId": "myapp_premium_annual",
      "purchaseDate": 1729747592000,
      "storefront": "USA",
      "storefrontId": "143441",
      "transactionId": "200009876543210",
      "type": "Auto-Renewable Subscription"
    }
  },
  "notificationType": "DID_CHANGE_RENEWAL_STATUS",
  "subtype": "AUTO_RENEW_ENABLED",
  "version": "2.0"
}

Understanding the Notification Fields

Key fields in the notification:

Top Level
- notificationType: The main event type (e.g., DID_CHANGE_RENEWAL_STATUS)
- subtype: Specific event subtype (e.g., AUTO_RENEW_ENABLED)
- version: API version (currently 2.0)
Renewal Info
- autoRenewProductId: Product identifier for the subscription
- autoRenewStatus: Current auto-renewal status (1 = enabled, 0 = disabled)
- renewalDate: Next renewal date in milliseconds
- renewalPrice: Price in minor units (e.g., 99990 = $99.99)
Transaction Info
- inAppOwnershipType: Purchase type (PURCHASED, FAMILY_SHARED, etc.)
- originalTransactionId: Original purchase identifier
- transactionId: Current transaction identifier
- purchaseDate: Purchase timestamp in milliseconds
- expiresDate: Subscription expiration timestamp

Processing Best Practices

Validation
- Always verify the notification's signature
- Check environment (Production vs. Sandbox)
- Validate bundle ID matches your app
Error Handling
- Implement exponential backoff for retries
- Log failed notification processing
- Set up alerts for repeated failures
Data Storage
- Store raw notifications for debugging
- Index by transactionId and originalTransactionId
- Keep audit logs of processed notifications

cURL Examples App Store Notification

Here's an example of the raw JSON data you'll receive from Apple (with randomized sensitive information):

{
  "signedPayload": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.secret"
}

Testing with CURL Examples 🧪

Here are some example CURL commands to test your notification system with different scenarios. Replace YOUR_FUNCTION_URL with your actual Cloud Function or Cloudflare Worker URL.

1. Subscription Renewal (Korean Market)

curl -X POST "YOUR_FUNCTION_URL" \
-H "Content-Type: application/json" \
-d '{
  "signedPayload": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.secret"
}'

2. Subscription Refund (German Market)

curl -X POST "YOUR_FUNCTION_URL" \
-H "Content-Type: application/json" \
-d '{
  "signedPayload": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.secret"
}'

3. Subscription Renewal (Brazilian Market)

curl -X POST "YOUR_FUNCTION_URL" \
-H "Content-Type: application/json" \
-d '{
  "signedPayload": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.secret"
}'

These examples demonstrate different notification types (renewal, refund, upgrade) across various markets with different currencies. The payloads are base64-encoded JWTs that will be decoded by the notification handler. You can use these to test your notification system's handling of:

Different Currencies & Regions
- Korean Won (KRW)
- Euro (EUR)
- Brazilian Real (BRL)
Various Notification Types
- DID_CHANGE_RENEWAL_PREF with UPGRADE subtype
- REFUND
- DID_RENEW
Price Formats
- Whole numbers (29 KRW)
- Decimal prices (6.99 BRL)
- Four-digit prices (14.99 EUR)

To use these examples:

Replace YOUR_FUNCTION_URL with your actual endpoint URL
Run the CURL command in your terminal
Check your configured notification channels (Discord/Telegram/Slack) for the formatted notification

What's Next 🚀

Now that you have real-time purchase notifications set up, you can:

Monitor your app's revenue in real-time
Quickly respond to refund requests
Track subscription patterns
Identify potential issues early
Make data-driven decisions for your app

Remember to star the repository if you found it helpful! ⭐️

Need Help 🤝

Create an issue on GitHub
Text me on Telegram

Acknowledgments 🙏

Special thanks to Ramazan Arslan for his initial implementation that inspired this project. I started by using his published version and then further developed it to make it simpler and more accessible for everyone to implement their own App Store server notifications handler.

This project is built with these amazing open-source packages:

@google-cloud/functions-framework - For serverless function development
Axios - For HTTP requests
base64url - For URL-safe base64 encoding
country-iso-3-to-2 - For country code conversion
jsonwebtoken - For JWT handling
date-fns-tz - For timezone-aware date formatting

Happy coding! 🎉

DEV Community: Kadir Melih Can

Setting Up App Store In-App Purchase Event Notifications: A Complete Guide

Table of Contents 📑

What We'll Build 🛠️

Setting Up Your Notification Channel 📢

For Discord:

For Telegram:

Setting Up and Deploying to Google Cloud Function ☁️

Setting Up and Deploying to Cloudflare Workers ⚡️

Connecting to App Store Connect 🔗

Using Adapty:

Using RevenueCat:

Direct App Store Connect Setup:

What You'll Get 📱

Example Notifications by Platform

Telegram Notification

Discord Notification

Advanced Features 🔧

Customizing Notifications

Error Handling

Timezone Support

Common Timezone Examples:

Date Format Examples:

Troubleshooting 🔍

Comparison of Google Cloud Functions vs Cloudflare Workers: Free vs Paid Tiers 🤔

Which One Should You Choose?

Cost Considerations 💰

Google Cloud Functions Free Tier

Cloudflare Workers Free Tier

Cost Estimation Examples

Cost Optimization Tips

Security Best Practices 🔒

Technical Details and Examples 🔧

Example App Store Notification

Understanding the Notification Fields

Processing Best Practices

cURL Examples App Store Notification

Testing with CURL Examples 🧪

1. Subscription Renewal (Korean Market)

2. Subscription Refund (German Market)

3. Subscription Renewal (Brazilian Market)

What's Next 🚀

Need Help 🤝

Acknowledgments 🙏