A concise technical guide comparing two fundamental strategies for receiving data updates from external systems: polling (asking repeatedly) and webhooks (being told automatically). Understanding both helps you choose the right integration pattern for your use case.
Polling is a client-driven pattern where your application repeatedly sends requests to a server at fixed intervals to check whether new data is available. For example, your app might call an API every 30 seconds asking 'do you have anything new for me?' The server responds whether or not new data exists, and your code processes it if present. This approach is straightforward to implement because it uses standard HTTP requests you already know how to make.
Webhooks are a server-driven pattern where an external service sends an HTTP POST request to a URL you provide (called an endpoint or callback URL) the moment an event occurs. Instead of you asking for updates, the provider pushes them to you in near real-time. For example, Stripe calls your /webhooks/stripe endpoint immediately when a payment succeeds. Your server must be publicly reachable and able to respond quickly with a 2xx status code to acknowledge receipt.
Polling wastes resources by sending requests even when no new data exists, which can mean thousands of empty responses over time. Webhooks are event-driven, so network traffic and compute are only consumed when something actually happens. Webhooks also deliver updates in milliseconds, while polling latency is bounded by your interval — a 60-second poll means up to 60 seconds of delay. For high-frequency events or time-sensitive workflows, webhooks are dramatically more efficient.
Use polling when the external service does not support webhooks, when you operate in a restricted network environment where inbound connections are blocked, or when you need to query for data on a schedule regardless of events. Use webhooks when you need real-time or near-real-time reactions to events such as payment confirmations, repository pushes, or form submissions. A hybrid approach is also common: use webhooks for instant notification, then poll or fetch details on demand to retrieve the full payload.
With webhooks, always verify the request signature provided by the sender (e.g., HMAC-SHA256 headers) to prevent spoofed payloads from untrusted sources. Respond immediately with a 200 OK and process the payload asynchronously using a queue to avoid timeouts causing the provider to retry. For polling, implement exponential backoff and respect rate limits to avoid getting your API key throttled or banned. In both patterns, design your handlers to be idempotent — processing the same event twice should not cause duplicate side effects.
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