How Node.js Webhook Consumers Should Handle Rate Limits and Dead-Letter Queues

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A technical guide for B2B SaaS platforms warns that successful HTTP delivery responses do not confirm that downstream business actions—like renewal reminders—actually completed on time. The core principle is that a consumer must treat the business deadline as the primary service-level objective, making rate limits, retry policies, and dead-letter decisions explicit parts of the system contract. Engineers are advised to define three key numbers before choosing queue technology: the business deadline, the sustainable downstream processing rate, and the maximum tolerable duplicate effect. The guide distinguishes between acknowledgement, negative acknowledgement, and dead-lettering as separate outcomes based on the future likelihood of success, not HTTP status codes. Duplicate handling is flagged as an application-level responsibility under at-least-once delivery, with uniqueness constraints on event IDs recommended to prevent stale or repeated actions.

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