API Polling vs. Webhooks

Introduction

When integrating external services into applications, two common approaches for data retrieval and updates are polling and webhooks. Each has its strengths and weaknesses, making them suitable for different use cases.

Polling

Polling is the process of repeatedly checking an external service or endpoint at regular intervals to retrieve updated information.

Think of it as asking, “Do you have anything new for me?” over and over, even if there’s no new data.

Key Characteristics:

• Resource-Intensive: Constant requests can put a strain on both the client and server, especially if updates are infrequent.
• Delayed Updates: Since updates are only retrieved during the polling interval, real-time information can be missed.
• Greater Control: Developers have full control over when and how the data is fetched, which can be useful in some scenarios.

Webhooks

Webhooks operate more like a notification system. Instead of continuously checking for updates, you provide the external service with an endpoint (a callback URL) on your application server.

Whenever a specific event occurs—like a payment confirmation or a shipment update—the external service calls your endpoint and sends the relevant data.

Key Characteristics:

• Real-Time Updates: Data is pushed to your application as soon as it’s available, making it ideal for time-sensitive applications.
• Resource-Efficient: Webhooks eliminate the need for constant requests, reducing server load and network usage.
• Dependency on Reliability: Missed notifications due to network issues are a potential risk, which makes implementing retry mechanisms essential.

When to Use Polling or Webhooks

Use Polling When:

• There are infrastructure or security limitations that make webhooks impractical.
• You need more control over the timing and frequency of data requests.
• Real-time updates are not critical, and periodic checks suffice.

Use Webhooks When:

• Your application requires instant data delivery, such as live notifications or event-driven updates.
• Resource efficiency is a priority, particularly in environments with high throughput.
• You can implement retry mechanisms to handle occasional missed notifications due to network disruptions.

Summary

• Polling offers control and works in constrained environments but can be inefficient and less responsive.
• Webhooks provide real-time updates and are resource-efficient, making them ideal for modern, event-driven systems.

By understanding these two methods, developers can choose the most appropriate approach based on their application’s requirements and infrastructure.