Rate-Limited Queues and Idempotent Retries for Webhook Enrollment Delivery

The article argues that HTTP webhook delivery for enrollment events should run through a durable work queue, with the consumer enforcing the receiver's rate limits. Retries are handled by the queue, while duplicate prevention is handled by the application using an idempotency record stored before a successful delivery is acknowledged. The author notes that a cron schedule acts only as a trigger, so a burst of accumulated work could flood the receiver unless rate and concurrency are controlled separately. A token bucket is suggested for request rate and a semaphore for concurrent requests, with per-tenant limiters so one noisy tenant cannot consume the whole allowance. The piece also stresses dead-letter handling for messages that exhaust retries, and explains the at-least-once trade-off created by the gap between a remote 2xx response and the local acknowledgement.