Webhooks vs API Polling: When to Use Which

The Two Models of Data Synchronization

When your application needs to know about changes in an external system, there are two fundamental approaches: polling and webhooks. Polling means your application periodically asks the external API "has anything changed?" Webhooks mean the external system tells your application when something changes.

Polling is the pull model: your application controls when to check for updates. You set an interval — every 30 seconds, every 5 minutes, every hour — and make API calls on that schedule. This is simple to implement but creates a tradeoff between responsiveness (shorter intervals) and efficiency (fewer API calls).

Webhooks are the push model: the external system initiates communication when events occur. Your application does not need to make any API calls to learn about changes — the information comes to you. This is more efficient and responsive but requires your application to be reachable via a public URL.

Advantages of Webhooks

Webhooks provide near real-time notifications. When a payment completes or a code push happens, your application knows within seconds. With polling, you would only discover the change at the next polling interval, which could be minutes or hours later.

Webhooks are significantly more efficient. Instead of making hundreds of API calls per day to check for changes (most of which return "nothing new"), you receive exactly the requests you need — one per event. This reduces your API usage, bandwidth, and the load on both your server and the provider's server.

Webhooks deliver richer data. A webhook payload typically contains the complete event data — the full order object, the entire commit diff, or the complete payment details. With polling, you often get a list of changed resource IDs and need additional API calls to fetch the full data.

Advantages of Polling

Polling is simpler to implement. You do not need a public URL, webhook endpoint, signature verification, or retry handling. A cron job or scheduled function that calls an API endpoint is straightforward to build, deploy, and debug. There is no inbound infrastructure to maintain.

Polling gives your application full control over timing. You decide when to check for updates, how often, and how to handle the results. With webhooks, events arrive on the provider's schedule, and your application must be ready to handle them at any time.

Polling is inherently reliable from your application's perspective. If your polling job fails, you simply retry on the next interval. With webhooks, if your endpoint is down when an event occurs, you rely on the provider's retry mechanism — which varies between providers and may eventually stop retrying.

When to Use Webhooks

Use webhooks when you need near real-time responsiveness. Payment notifications, chat messages, deployment status updates, and user authentication events all benefit from immediate delivery. Users expect instant feedback for these interactions.

Use webhooks when the event frequency is low relative to the polling frequency you would need. If events happen a few times per hour but you would need to poll every 30 seconds for acceptable latency, webhooks eliminate thousands of wasted API calls.

Use webhooks when the provider offers them with good reliability guarantees. Major providers like Stripe, GitHub, and Shopify have robust webhook infrastructure with retries, signing, and delivery logs. Leveraging this infrastructure is almost always better than building your own polling system.

For local development with webhooks, tools like ReqPour bridge the gap between the provider's servers and your localhost by providing a public endpoint and relaying requests to your local machine.

When to Use Polling

Use polling when the external API does not support webhooks. Many APIs still only offer REST endpoints without webhook capabilities. In these cases, periodic polling is your only option.

Use polling when you need to pull large datasets or batch process changes. Some APIs have "list changes since" endpoints optimized for batch retrieval. Polling these endpoints on a schedule can be more efficient than processing individual webhook events, especially for data synchronization jobs.

Use polling as a fallback alongside webhooks. The most robust approach is to use webhooks for real-time notifications and a periodic polling job to catch anything that might have been missed due to webhook delivery failures. This "belt and suspenders" approach is common in payment processing.

Combining Both Approaches

The best practice for production systems is to use webhooks as the primary notification mechanism and polling as a reconciliation safety net. Webhooks give you real-time updates for most events, and a periodic polling job catches any events that slipped through due to webhook delivery failures.

For example, use Stripe webhooks to handle payment_intent.succeeded events in real time, but also run a daily job that lists recent payments and verifies your database matches Stripe's records. This catches edge cases where a webhook was lost or your handler had a bug.

During development, ReqPour's request history and replay features help you build reliable webhook handlers. You can inspect every incoming event, replay failed deliveries, and verify your handler processes each event correctly — reducing the need for polling-based reconciliation in production.