As APIs become more central to how systems communicate and integrate, the need for real-time notifications grows exponentially. Polling an API repeatedly to check for updates is inefficient, costly, and rarely scalable. That’s where webhooks come in — a simple yet powerful mechanism that allows APIs to proactively notify external systems when specific events occur.

In this article, I’ll explore why webhooks are essential in modern API design, and dive into a set of best practices to ensure they are implemented reliably and securely.

Why Webhooks Matter

Webhooks enable event-driven architectures, meaning clients don’t need to constantly check if something has changed. Instead, they receive a push notification as soon as a relevant event occurs.

Some key benefits include:

  • Reduced latency: Systems react instantly to events.

  • Efficiency: No need for constant API polling.

  • Improved user experience: Systems can provide real-time updates to end users.

But to deliver these benefits consistently, webhooks must be built with resilience and flexibility in mind.

Best Practices for Implementing Webhooks

Notify on Every Status Change
APIs should emit a webhook for every change of status in a resource. Whether it’s an order being shipped, a payment being confirmed, or a transfer being completed, clients must be kept in the loop with accurate and timely updates.

Implement a Clear Retry Policy
Failures can and will happen. If the receiving system doesn’t respond with a 2xx HTTP status, the originating system must retry the webhook delivery. Retries should follow an exponential backoff strategy to avoid flooding the recipient.

Notify Users After Exhausting Retries
If, after several retry attempts, the destination still does not return a 2xx response, the system should stop trying and send an email to the client, explaining:

  • The specific event that failed
  • That the webhook won't be retried again
  • Instructions on how to manually recover from the failure
  • This promotes transparency and avoids silent failures.

Allow Manual and Bulk Redelivery
Clients should be able to manually trigger redelivery of failed webhooks. Even better, systems should provide an interface or API to resend events in bulk, helping with large-scale recovery efforts or testing scenarios.

Send Only Necessary Data
To minimize payload size and reduce the risk of data leakage, webhook payloads should contain only the essential information required by the client to handle the event. If more data is needed, the client can fetch it using the event’s associated resource ID.

Use Signatures to Verify Authenticity
Security is paramount. Every webhook should include a signature header, generated using a secret known only to the API provider and the client. Clients should validate the signature to ensure the webhook is genuinely from the source and hasn’t been tampered with.

Allow Clients to Register Webhook URLs via API
APIs should allow clients to programmatically register their webhook URLs, along with custom headers if needed. This makes automation easier and helps manage environments like staging and production more effectively.

Enable Granular Event Subscription
Not every client wants to receive every single event. APIs should support granular subscriptions, allowing clients to specify the resources and statuses they care about. For example:

ORDERS.*  
PAYMENTS.PAID  
PAYMENTS.CANCELED  
TRANSFERS.COMPLETED

This level of control reduces noise and allows clients to tailor event consumption to their specific use cases.

Conclusion
Webhooks transform APIs from passive data providers into active communicators. But with great power comes great responsibility — poor implementations can lead to missed events, security vulnerabilities, and frustrated clients.

By following the best practices outlined above, API providers can ensure that their webhook systems are reliable, secure, and developer-friendly, ultimately leading to better integrations and happier users.

Photo by Brett Jordan on Unsplash