BullMQ worker with retries + dead-letter

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                  import { Queue, Worker } from 'bullmq';
import IORedis from 'ioredis';

const connection = new IORedis(process.env.REDIS_URL!);

export const emailQueue = new Queue('email', { connection });

export const emailWorker = new Worker(
  'email',
  async (job) => {
    // sendEmail(job.data)
    return { sent: true };
  },
  {
    connection,
    concurrency: 5
  }
);

emailWorker.on('failed', async (job, err) => {
  if (!job) return;
  if ((job.attemptsMade ?? 0) >= (job.opts.attempts ?? 1)) {
    // dead-letter pattern: re-enqueue into a separate queue for investigation
    await new Queue('email-dlq', { connection }).add('dead', { original: job.data, error: err.message });
  }
});

Background jobs will fail in production, so I like having a predictable story for retries and poison messages. BullMQ is a solid middle ground: Redis-backed, straightforward, and good enough for most apps. I set explicit attempts and backoff, and when a job keeps failing I push it to a DLQ (dead-letter queue) for human inspection instead of retrying forever. For side-effecting work (emails, payments), I include an idempotency key in the job payload and design the handler to be safe on re-run. The core insight is that retries must be safe by design—don’t rely on ‘it probably won’t run twice’, because eventually it will.

Mateo Rodriguez

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BullMQ worker with retries + dead-letter

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