Webhook vs Polling: Which Integration Pattern Should You Use?

Most integration decisions get made by default: the first engineer who touches the code picks polling because it's familiar, and that choice becomes permanent. Six months later, someone notices the integration is 90 seconds behind real time and the API bill is inexplicably high. Understanding the trade-offs upfront avoids the rewrite.

How Polling Works (and Where It Breaks)

Polling is simple: your code runs on a schedule — every 30 seconds, every minute, every five minutes — and issues a GET request to the external API asking "has anything changed since I last checked?" If yes, it processes the new data. If no, it discards the response and waits for the next interval.

The problem is the gap between intervals. If you poll every 60 seconds and an event fires one second after a poll completes, your system won't know about it for 59 seconds. For anything time-sensitive — a payment confirmation, a support ticket, a new lead — that latency is usually unacceptable.

The instinct to fix this by polling more frequently makes things worse. Moving from 60-second to 5-second intervals multiplies your API call volume by 12x. You burn through rate limits faster, pay more for compute, and put unnecessary load on the third-party service. Many public APIs will throttle or ban clients that poll too aggressively. You end up working against the system you're trying to integrate with.

There's also the wasted bandwidth problem. If an external system only changes a few times per day, polling every minute means roughly 99.9% of your requests return nothing useful. You're paying for that compute and that API quota anyway.

How Webhooks Work

Webhooks flip the model. Instead of your system asking the external service "did anything change?", the external service calls your endpoint the moment something does. You register a URL with the provider, and they send an HTTP POST to that URL whenever a relevant event occurs — a payment succeeds, a form is submitted, a record is updated.

The latency drops to near-zero. The moment Stripe processes a payment, your endpoint knows. No polling interval, no unnecessary API calls, no rate limit risk from idle requests.

But webhooks come with requirements. Your endpoint must be publicly reachable — which rules out local development without a tunnel like ngrok or a dedicated staging environment. You need to verify the signature on every incoming request to confirm it came from the legitimate source and not a bad actor who discovered your endpoint URL. And your handler must be idempotent: the same event may arrive more than once (more on this below), and processing it twice should not cause double-charges, duplicate records, or conflicting state.

The Decision Table

Rather than a general preference, think of it as a fit-for-purpose choice:

Use polling when: the third-party service doesn't support webhooks (it still happens, especially with older enterprise tools); you need bulk data snapshots rather than event-driven updates; eventual consistency of a few minutes is perfectly acceptable; or you're working in a network environment where inbound connections are blocked.

Use webhooks when: real-time response matters — payment confirmations, user sign-ups, inbound support requests; you want to reduce outbound API call costs; you need to react to events rather than periodically check for them; or you're building anything that feeds into a user-facing workflow where latency is visible.

In practice: if the external service supports webhooks and your use case involves reacting to events, always prefer webhooks. Reserve polling for bulk sync jobs and legacy systems that leave you no choice.

One Gotcha with Webhooks: Delivery Guarantees

Webhook providers deliver on a best-effort basis. Your endpoint might be down during a deployment. The network between the provider and your server might drop a packet. The provider might have a bug that sends the same event twice. You need to design for all of these.

The standard approach: acknowledge receipt immediately with a 200 response (even before you've finished processing), then handle the actual work asynchronously via a queue. If your endpoint returns a 500 or times out, a well-behaved provider will retry — which is why idempotency matters so much. Track which event IDs you've already processed and skip duplicates. For events that fail even after retries, route them to a dead-letter queue so they don't disappear silently — you want to inspect and replay them manually if needed.

Neither polling nor webhooks are inherently superior. Each is a tool for a specific job. The mistake is picking one by default rather than by intent. Define your latency requirements, check what the upstream system supports, and design your handler to be resilient to failure regardless of which pattern you choose.

---

If you're designing an integration architecture and want a second opinion on the right pattern, reach out to our team. We've built webhook handlers and polling pipelines across dozens of production integrations — and we know where each approach breaks down.