The choice between request-response and event-driven communication patterns is one of the most consequential architectural decisions in distributed system design. It determines how services couple to each other, how failures propagate, how the system scales under load, and how difficult it is to trace the flow of data through the system when things go wrong. Most teams treat it as a technology choice — Kafka versus REST — when it is primarily a design choice about how services should relate to each other.

The polling versus webhooks decision is frequently made on the basis of what the API provider finds easiest to implement rather than what serves consumers best. Polling is easier to provide — it requires no additional infrastructure beyond the existing API endpoints. Webhooks require the provider to maintain delivery infrastructure, handle failures, implement retry logic, and manage consumer endpoint registration. The provider’s preference for polling is understandable. For the consumers who pay the operational cost of polling, it is not a neutral choice.