Webhook vs Polling: When to Use Each

You need to know when something changes in someone else's system. Two options: poll — ask "anything new?" on a schedule — or subscribe to webhooks and let the system push events to you.

Both work. Both have failure modes. This guide is about choosing the right one for your use case, and when a hybrid is the honest answer.

Polling: ask on a schedule

Your service hits GET /api/orders?since=last_seen_at every 30 seconds. Process whatever comes back. Update last_seen_at. Repeat.

Pros:

• Stateless — no infrastructure for receiving inbound calls.
• Simple failure mode — if the poll fails, the next one catches up.
• Strong consistency — you control when reads happen, so you can read-your-write.
• Works behind firewalls and from internal services that can't expose public endpoints.

Cons:

• Latency proportional to poll interval. 30-second polling means up to 30 seconds of delay.
• Wasted requests when nothing changed. 99% of polls return empty.
• Rate limits — most APIs cap requests/min, so polling at scale across many resources gets expensive fast.
• Hard to coordinate across multiple instances of your service — who polls?

Webhooks: push events

The provider POSTs to your endpoint when something happens. Your handler processes the event. You return 200.

Pros:

• Sub-second latency — events arrive when they happen.
• Efficient — zero requests when nothing's happening.
• No coordination — the provider knows where to send.

Cons:

• Requires a public HTTPS endpoint (or a tunnel — but that's its own complexity).
• Signature verification, idempotency, retry handling — the receiver carries the complexity.
• Lost webhooks are silent — if your endpoint was down and the provider retried for a while and gave up, you have no signal.
• Hard to debug — payloads arrive asynchronously, often without good logs.

When to pick each

Pick polling when:

• You're inside a corporate firewall and can't expose a public endpoint.
• The provider doesn't offer webhooks (still common with legacy APIs).
• Latency under a minute isn't critical.
• You need transactional consistency — your reads must reflect your latest writes.
• The number of resources you're tracking is small and bounded.

Pick webhooks when:

• You need sub-second latency for UX or business reasons.
• The number of resources you're tracking is large (millions of users, all of whom might generate events).
• You can expose a public HTTPS endpoint and handle the operational complexity.
• You want to scale without scaling polling cost linearly.

The hybrid pattern

Most production systems use both:

1. Webhooks for the fast path. Subscribe to events for low-latency notification. Handle them idempotently with signature verification.
2. Polling as a safety net. Every hour, run a reconciliation poll that fetches state for the last 24 hours of activity and compares against your database. Anything missing? Your webhook was lost.

This pattern catches the failure modes of pure webhooks (silent losses) while preserving the latency benefit. The cost is one extra background job and a state reconciliation routine — well worth it for systems where missing an event is expensive (billing, identity, fulfillment).

The honest answer

If you only have one to invest in: webhooks, with idempotency and good observability. The latency win is real, the operational complexity is manageable with modern tools (this is what HookSense is for — inspection and replay when webhooks misbehave).

If you have an existing polling-based architecture and it's working: don't migrate to webhooks just because they're newer. Webhooks add complexity to a system that polls reliably.

Further reading

• Webhook vs polling — glossary
• Webhook idempotency
• Building new API integrations