Webhook vs API Polling: Choosing How Two Systems Should Talk
Two systems need to stay in sync, and somebody has to decide how the second one finds out when the first one changes. That decision, made early and often without much thought, quietly shapes how fast an integration feels, how much it costs to run, and how many support tickets get raised when something goes stale. Webhooks and polling are the two answers most teams reach for, and neither is universally correct.
Key Takeaways
- Polling means a client repeatedly asks an API “has anything changed?” on a fixed schedule, whether or not the answer is yes.
- A webhook means the source system sends an event to a receiving endpoint the instant something happens, with no request needed from the receiver.
- Polling is simpler to build and debug because the requesting side controls the entire exchange, but it wastes calls on empty responses and introduces a delay between the event and its discovery.
- Webhooks cut that delay to near zero and reduce wasted traffic, but they require a publicly reachable endpoint, retry handling, and a way to verify that a payload genuinely came from the sender.
- Many mature integrations use both: webhooks for near-instant updates and a periodic poll as a safety net that catches anything a missed webhook let slip through.
Most teams pick whichever pattern the API they are integrating with happens to support, and that is often the right call. But when there is a genuine choice, whether building an internal service or scoping a third-party integration, the trade-offs below decide which approach will hold up once real traffic hits it.
What each pattern actually does
Polling is a request-response loop the client owns entirely. Every thirty seconds, every minute, or every hour, the client calls an endpoint and asks for the current state or a list of changes since the last check. If nothing changed, the response says so and the client waits for its next scheduled turn. This is the same pattern behind a browser refreshing an inbox or a dashboard checking for new orders, and it works precisely because the client is always in control of when it asks.
A webhook flips that control. Instead of the client asking, the source system holds a list of URLs it has been told to call whenever a defined event occurs, and it calls them directly, usually with an HTTP POST carrying the event data as JSON, the same request method and body semantics the IETF formalised in RFC 9110 back in 2022 when it separated core HTTP behaviour from any single protocol version. The receiving service does not ask anything; it simply has to be listening, ready to accept a request at any moment and respond quickly enough that the sender does not treat the delivery as failed. Stripe’s own documentation on webhooks describes this well: the sending platform pushes an event as soon as it happens, and the receiver’s job shrinks to acknowledging, storing, and acting on it.
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Where polling still wins
Polling’s biggest advantage is how little it demands of the receiving system. There is no need for a public endpoint, no need to worry about firewall rules letting an external service reach in, and debugging is straightforward because every exchange starts with a request the client itself made a moment earlier. If something breaks, the client’s own logs show exactly what was asked and when.
It also fits situations where near-instant updates simply are not needed. A nightly stock reconciliation, a weekly report pull, or a background sync that only matters if it completes within the hour has no real use for sub-second delivery. Building a webhook receiver for that kind of workload adds infrastructure, security surface, and monitoring burden for a benefit nobody will notice. The cost of polling in this case is a handful of scheduled requests, most of which will return “nothing changed,” and that cost is usually trivial next to the operational simplicity gained.
Polling frequency is also a lever a team controls entirely on its own side. If load on the source API becomes a concern, the interval can be widened without coordinating with anyone else. A webhook sender, by contrast, decides the pace of delivery, and the receiver has comparatively little say in it.
Polling trades a small, predictable delay for a system that is far easier to reason about and debug when something goes wrong.
Where webhooks earn their complexity
The moment freshness genuinely matters, the calculation flips. A payment confirmation, a support ticket status change, or a shipment update that a customer is actively watching all benefit from arriving the instant they happen rather than up to a polling interval later. Google Cloud’s Pub/Sub documentation makes a related point about push-based delivery generally: event-driven notification removes the artificial delay a polling interval imposes, and it does so without the receiving side wasting cycles on repeated checks that come back empty.
Adoption backs up the shift: Postman’s 2023 State of the API report, drawn from a survey of over 40,000 developers, found that 36% were already using webhooks to wire systems together rather than polling for updates. That immediacy is not free. A webhook receiver has to accept inbound requests from the open internet, which means authenticating every payload, typically by verifying a signature the sender attaches to each delivery, so a receiver can be certain a request genuinely came from the expected source and was not forged or replayed. It also has to handle delivery failures gracefully: networks drop packets, receivers go down for maintenance, and a sender that gives up after one failed attempt will silently lose events unless it retries with backoff and the receiver can tolerate occasionally processing the same event twice.
Server room with rows of illuminated network racks
Designing an integration around the right pattern
Choosing between the two is rarely about which pattern is objectively better; it is about matching the pattern to how time-sensitive the data actually is and how much operational overhead a team can absorb. A useful question is what happens if an update arrives five minutes late. If the honest answer is nothing, polling on a sensible interval is probably the pragmatic choice. If a five-minute delay would visibly frustrate a user or break a downstream process, a webhook is worth the extra engineering.
Teams building integrations at this scale often end up doing exactly what a well-designed general-purpose connection does anyway: exposing both, letting the consumer choose, and documenting the guarantees of each clearly enough that nobody has to guess. This is the kind of decision that sits underneath what people usually mean when they talk about connecting two systems together in the first place, a topic covered in more depth in Arch‘s guide on the subject.
A hybrid approach is common in production systems for good reason. Webhooks handle the fast path for the events that matter, and a low-frequency poll runs alongside as reconciliation, catching anything a dropped webhook delivery let through unnoticed. That combination costs more to build than either pattern alone, but it removes the single point of failure that a pure webhook design otherwise carries. The traffic numbers back the direction of travel: messaging platform Customer.io reported that webhook volume on its own systems grew two to three times year-over-year in 2025, the second-fastest-growing delivery channel it tracks.
Person typing on a laptop keyboard with a coffee cup nearby
Frequently Asked Questions
Is a webhook always faster than polling?
Yes, in terms of raw delivery time, because a webhook is sent the instant the triggering event occurs rather than waiting for a client’s next scheduled check. The practical gap depends on how tight the polling interval is; a one-second poll is close to instant too, but at a traffic cost most systems cannot sustain.
Why do webhooks need signature verification?
A webhook endpoint sits on the open internet and accepts requests without the receiver initiating anything, so nothing about the request format alone proves it came from the expected sender. A signature computed with a shared secret lets the receiver confirm the payload was not forged or tampered with in transit.
Can polling and webhooks be used together?
Yes, and this combination is common in production integrations. Webhooks deliver the fast path for time-sensitive events, while a periodic poll acts as a safety net that catches anything lost to a failed or missed webhook delivery.
What happens if a webhook delivery fails?
A well-built sender retries failed deliveries with increasing delays between attempts and eventually gives up after a defined number of tries, often notifying the receiver’s team that delivery is failing. Without retry logic, a single dropped request means the event is lost entirely unless a reconciliation poll catches the gap.
Does polling waste server resources?
It can, particularly when the interval is short relative to how often data actually changes, since most requests return an unchanged result. Widening the interval or switching to a webhook for the highest-value events reduces this waste without losing the events that matter.
