Get Notified on Telegram When Your EAS Build Completes! 💬

Learn how to get instant Telegram alerts when your EAS build or submission completes. It’s perfect for developers who want to stay updated without constantly checking build status manually.

You’ll learn how to create a Telegram bot, set up a webhook with EAS, build an API handler using Expo Router, and deploy it with EAS hosting. The approach is flexible and can be adapted to Slack, email, or other notification services.

What's inside

• Creating a Telegram bot and obtaining bot token and group ID
• Setting environment variables for Telegram integration
• Writing an API handler to send Telegram messages on build completion
• Creating and managing EAS webhooks for build notifications
• Validating webhook signatures for security
• Deploying the webhook API with Expo hosting
• Testing the notification by triggering an EAS build
• Viewing and interacting with build notification messages on Telegram

Creating a Telegram bot and obtaining bot token and group ID

To send Telegram notifications, you first create a Telegram bot using the BotFather bot. You start a chat with BotFather, issue the /newbot command, and follow prompts to name your bot and get a bot token.

Next, create a Telegram group and add your bot to it. You then retrieve the group’s chat ID by querying the bot’s updates with a curl command. This chat ID and the bot token are essential for sending messages to the group.

Setting environment variables for Telegram integration

Store your Telegram bot token and group chat ID as environment variables in your project. This keeps sensitive information out of your codebase and makes it easy to update tokens or IDs without code changes.

For example, set TELEGRAM_BOT_TOKEN and TELEGRAM_GROUP_ID in your environment configuration. Your API handler will read these variables to authenticate and target the correct chat.

Writing an API handler to send Telegram messages on build completion

Create an API route (e.g., api/easWebhook.ts) using Expo Router that listens for EAS webhook calls. This handler extracts the build status and other details from the webhook payload.

It constructs a message including build status, platform, commit message, and artifact links. Then it sends this message to Telegram by posting to the Telegram Bot API endpoint using the bot token and chat ID.

The handler uses a POST request with JSON headers and body to send the message.

Creating and managing EAS webhooks for build notifications

Use the eas webhook CLI commands to create and manage webhooks. Run eas webhook:create and specify that the webhook is for builds.

Provide the URL of your deployed API handler as the webhook endpoint. You also set a webhook secret, a random string used to verify incoming webhook requests.

You can list existing webhooks with eas webhook:list and update them with eas webhook:update to change URLs or secrets.

Validating webhook signatures for security

Your API handler verifies that incoming webhook requests are genuinely from Expo by checking the expo-signature header.

It uses the webhook secret and cryptographic hashing (via Node’s crypto module) to compute a signature of the request body and compares it to the header.

If the signatures don’t match, the handler rejects the request with a 403 status. This prevents unauthorized or spoofed webhook calls.

Deploying the webhook API with Expo hosting

Configure your Expo app to output a server build for web by setting output: "server" in your app.config.js or app.json.

Export the web build and API routes using npx expo export --platform web. Then deploy your project with eas deploy --prod.

Make sure your API route has the correct naming convention (e.g., prefix with +api) so Expo recognizes it as an API endpoint.

Once deployed, update your EAS webhook URL to point to your live API endpoint.

Testing the notification by triggering an EAS build

Trigger a new EAS build with a command like eas build --platform ios --profile production.

Once the build completes, Expo will send a webhook request to your API handler, which sends a Telegram message.

You’ll receive a notification in your Telegram group with build status, commit info, and links to download the build artifact.

Viewing and interacting with build notification messages on Telegram

The Telegram bot sends a message including emojis to indicate build success or failure, the platform, commit message, and clickable links to the build artifacts.

This lets you quickly access the build without manually checking the Expo dashboard. You can share the link with teammates or install the build directly on your device.

Resources

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