background-jobs-queue-expert

# Background Jobs & Queue Expert [English](#english) | [Bahasa Indonesia](#bahasa-indonesia) --- <a name="english"></a> ## English ### Description A deep-dive expert guide for implementing advanced background job queues using BullMQ v5, Trigger.dev v3, and Inngest. This skill focuses purely on the mechanics of robust job processing: delayed jobs, job deduplication, concurrency limits per-tenant, strict idempotency, dead letter queues (DLQ), and job priorities. ### Trigger Conditions - Implementing job queues in a backend application. - Dealing with flaky third-party APIs that require backoff and retry. - Designing Dead Letter Queues (DLQ) for failed background tasks. - Implementing job deduplication and prioritization (e.g., premium user tasks first). - Offloading heavy compute tasks (video processing, PDF generation, bulk email) from the main request loop. ### Advanced Concepts 1. **Idempotency**: Every background job MUST be idempotent. It should be safe to run the exact same job multiple times without creating duplicate side-effects (e.g., charging a customer twice). 2. **Job Deduplication**: Use deterministic job IDs based on payload hash or business logic (e.g., `invoice_gen_{invoiceId}`) to prevent the same job from being enqueued multiple times. 3. **Dead Letter Queues (DLQ)**: Jobs that fail repeatedly after all backoff retries must be moved to a DLQ for manual inspection. Never let a poison pill job block the queue. 4. **Concurrency and Rate Limits**: When cal...