Short answer: use an at-least-once message queue with delayed retries, an idempotent Node.js worker, and a dead-letter queue for failed SaaS jobs; use cron only to trigger work that is then drained by workers. For an e-commerce system, that means a failed order-confirmation or inventory-sync job becomes a durable message. A worker claims it, records the outcome, and either acknowledges it, schedules a bounded retry, or sends it to a dead-letter queue (DLQ) for inspection. This design gives op...