If you have ever connected two systems - a POS to an accounting platform, a payments terminal to a stock tool, an online ordering app to a kitchen display - someone has eventually had to decide how data moves between them. Two patterns dominate: polling and webhooks. Neither is exotic. Both have real trade-offs. Understanding the difference will help you ask better questions of any vendor or developer you work with.
Polling: asking over and over
Polling is the simpler concept to grasp. Your system checks another system on a schedule - every minute, every five minutes, every hour - and asks "has anything changed?". It is like refreshing your inbox manually. Most of the time the answer is no. Occasionally it is yes. Either way, your system had to make the trip. The upside is simplicity: polling requires no special configuration on the other end, works even with older APIs, and is easy to reason about. The downside is that it is inherently delayed and wasteful. If a sale hits your POS at 12:01 and your sync runs at 12:05, you have a four-minute lag. At scale, dozens of systems polling dozens of endpoints adds up to a lot of unnecessary traffic and load.
Webhooks: being told when something happens
A webhook flips the model. Instead of your system asking repeatedly, the other system calls you the moment an event occurs. A payment is processed, a stock level drops below threshold, an order is placed - the source system sends an HTTP request to a URL you provide, carrying the event data. Your system receives it, processes it, done. The result is near-real-time data flow with minimal wasted calls. For a hospitality or retail business, that difference is tangible: stock figures that update within seconds of a sale, payment confirmations that reach your accounting system before the customer has left the counter.
The catch is that webhooks introduce their own complexity. You need a publicly reachable endpoint. You need to handle failures - what happens if your server is down when the webhook fires? You need retry logic and, ideally, some way to verify that incoming requests are genuinely from the system you expect. These are solvable problems, but they are real ones.
What this means for POS, payments and stock
For most hospitality and retail integrations, the choice between polling and webhooks is less about preference and more about what the vendor supports and what latency your operations can tolerate. End-of-day accounting reconciliation? Polling on a nightly schedule is probably fine. Real-time stock depletion shared across multiple sites? You want webhooks, or you will be managing phantom inventory. Payment status updates? Webhooks mean your system knows a transaction is settled in milliseconds, not minutes.
If you are evaluating a new platform or asking a developer to build an integration, the questions to ask are: does the system offer webhooks for the events that matter to us? If so, does it include retry logic for failed deliveries? If not, how frequently can we poll without hitting rate limits? The answers tell you a lot about how reliable the data flow will be in practice. For a deeper look at what makes integrations hold together day-to-day, see POS integration that actually works.
Picking the right pattern - or combining both
In practice, many well-built systems use both. Webhooks handle the real-time critical path - payments confirmed, orders placed, stock adjusted. Polling runs as a periodic reconciliation pass to catch anything that slipped through: a webhook that fired when your endpoint was briefly unavailable, an event the source system quietly dropped. That combination - webhooks for speed, polling for resilience - is a sensible default for anything where data accuracy matters.
If you are connecting your POS to your accounting platform, the same logic applies: fast event delivery for live transactions, a nightly check to confirm the numbers match. We cover that in more detail in connecting your POS to accounting. If you are building or reviewing an integration and want a second opinion on the architecture, tell us about your project.
Frequently asked questions
- What is a webhook in simple terms?
- A webhook is a way for one system to automatically notify another system the moment an event happens - like a payment being processed or an order being placed. Rather than your system repeatedly checking for updates, the source system sends the data to you in real time. You provide a URL, and the other system calls it whenever there is something to report.
- What is the difference between webhooks and polling?
- Polling means your system checks another system on a schedule to see if anything has changed - even if the answer is usually no. Webhooks invert that: the other system contacts you the moment an event occurs. Webhooks are faster and more efficient; polling is simpler to set up and can act as a fallback when webhooks are unavailable.
- When should I use polling instead of webhooks?
- Polling makes sense when the source system does not support webhooks, when data freshness requirements are low (for example, a nightly accounting sync), or as a reconciliation safety net alongside webhooks. For anything time-sensitive - live stock levels, payment confirmations, order routing - webhooks are the better fit where available.