APIs and webhooks are common ways marketing systems exchange data. An API lets one system request or update information through defined endpoints; a webhook sends a notification when an event occurs. Many integrations use both, so the decision is about the interaction pattern rather than choosing one technology for every task.
An API supports request-and-response work
A system can call an API to retrieve records, update fields, create audiences, or check status. Polling an endpoint on a schedule is useful when updates can be periodic or when the receiving system needs to reconcile a complete set of records.
Polling too frequently can waste resources or hit rate limits, while polling too slowly delays updates. Plan for authentication, pagination, rate limits, version changes, and the point at which a partial failure should be retried.
A webhook notifies about an event
A webhook is typically an HTTP request sent to a configured endpoint when a source system records an event, such as a form submission or subscription change. This can reduce waiting and unnecessary repeated checks when low-latency event delivery matters.
Webhook delivery is not the same as guaranteed processing. The destination may be unavailable, messages may be retried, and events can arrive more than once or out of order. The receiving system should validate the sender and payload, acknowledge safely, and process idempotently.
Choose based on timing and recovery
Use an API request when the consumer needs to ask for data on demand, perform a backfill, or reconcile missed events. Use a webhook when the producer can notify the consumer promptly about a change. A robust design often combines webhook notifications with an API fetch for full details or recovery.
Define a stable event identifier, retry schedule, dead-letter or error review path, and ownership for schema changes. Monitor delivery latency and failures so teams can distinguish a quiet period from a broken integration.
Protect data and test edge cases
Limit fields to what the integration needs, protect credentials, verify signatures where supported, and apply the organization’s consent and retention rules. Test duplicate events, slow responses, expired credentials, malformed payloads, and recovery after downtime.
APIs provide a controlled request surface; webhooks provide event-driven notifications. Reliability comes from the surrounding validation, monitoring, and recovery design.
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