Shopify

Webhooks

Webhooks in Shopify serve as a powerful tool to keep your app in sync with the store's data or to execute actions in response to specific events. Unlike continuous polling, which can be resource-intensive, webhooks provide a more efficient method to receive updates or changes directly from Shopify. When a specified event occurs in a Shopify store, Shopify sends a webhook to the configured URL endpoint of your app, delivering a payload of data relevant to the event. This mechanism allows for real-time data processing and integration, enabling apps to react promptly to changes in the store.

Topics

Webhook topics in Shopify define the specific events that trigger webhooks to send data to your specified URL endpoint. Each topic corresponds to a particular event in Shopify, such as the creation of an order, a product update, or a customer registration. When you subscribe to a webhook topic, Shopify will notify your application in real-time by sending a POST request to your webhook URL whenever the event occurs. List of topics.

Tests

If needed, the Shopify CLI can be used to send a webhook request to any address using npm run shopify webhook trigger.

HTTPS Webhooks

Security and Verification

Shopify ensures the security and integrity of webhooks through the use of HTTPS and digital signatures. Each webhook request includes a base64-encoded X-Shopify-Hmac-SHA256 header. This header contains a digital signature generated using the app's client secret and the data sent in the request, allowing the receiving app to verify that the webhook was indeed sent by Shopify. Verification Process

1. Extract the HMAC Header: Upon receiving a webhook, extract the X-Shopify-Hmac-SHA256 header from the request. This header contains the base64-encoded digital signature of the payload.
2. Compute the HMAC Digest: Using the app's client secret, compute an HMAC digest of the POST request body. The digest should be computed using the SHA256 hash function.
3. Compare the Signatures: Decode the base64-encoded signature from the header and compare it to the HMAC digest you've computed. If they match, the webhook is verified.

This process ensures that the webhook was sent by Shopify and that the data has not been tampered with during transmission. Handling Webhook Payloads The body of a webhook request contains the data payload, which is JSON formatted. Your app needs to parse this JSON payload to extract and use the data. It's crucial to verify the webhook before processing the payload to ensure the data's integrity and security.

Best Practices

Shopify has a list of best practices that we should keep in mind for the future to reflect and anticipate eventual issues.

• 1. Respond Quickly: Webhook endpoints should acknowledge receipt by returning a 200 series status code quickly. Processing should be handled asynchronously to avoid timeouts.
• 2. Secure Endpoints: Use HTTPS for your webhook endpoints to ensure encrypted communication. Regularly rotate your client secret and update your webhook verification logic accordingly.
• 3. Idempotency: Design your webhook processing to be idempotent. This means that receiving the same webhook multiple times should not result in duplicated actions.
• 4. Error Handling and Retries: Implement robust error handling. Shopify will retry webhooks if your endpoint returns an error response. Be prepared to handle these retries gracefully.
• 5. Logging and Monitoring: Maintain logs of received webhooks and their processing status. Monitoring these logs can help identify issues with webhook processing or receipt.
• 6. Data Processing: Given the real-time nature of webhooks, ensure your app can process data efficiently and scale as needed to handle varying loads.
• 7. Security: Always verify webhook signatures before processing the payload. This step is crucial for ensuring the webhook was actually sent by Shopify and that the data hasn't been altered.

For more detailed information and updates, refer to the Shopify Webhooks Documentation.