Polling vs Webhooks: When to Use One Over the Other

In the context of integrating systems in SaaS products, the choice between polling and webhooks involves tradeoffs related to freshness, cost, reliability, and complexity, with both methods often being used in combination. Polling is a client-driven model where an application periodically checks a third-party API for updates, offering universal availability and control over execution but potentially leading to stale data and increased operational overhead. Webhooks, conversely, push updates as events occur, providing fresher data and reduced API usage but are limited by inconsistent support, provider-dependent behaviors, and delivery complexities. Virtual webhooks offer a middle ground by simulating webhook behavior for APIs lacking native support, enabling deterministic, change-based delivery without requiring polling logic. The decision to use polling, native webhooks, or virtual webhooks should be guided by specific needs such as data freshness, event volume, and the degree of provider support, with an understanding of the tradeoffs in delivery semantics, retries, and billing implications.