Queue backed by durable persistent storage

An in-memory queue — a plain array, a Map, or a setInterval drain loop — lives entirely in the Node.js process heap. When the process restarts after a deploy, a crash, or an OOM kill, every pending email in that queue vanishes. Recipients who triggered a password-reset or order-confirmation during that window never receive it. CWE-400 covers resource exhaustion from unbounded growth; here the risk is the inverse — the store has zero durability. ISO-25010:2011 reliability.fault-tolerance requires components to survive fault conditions; in-process storage is the antithesis of that property.

Replace any in-process queue with BullMQ backed by Redis, or pg-boss backed by PostgreSQL in lib/queue.ts. Initialize the connection at startup with an explicit URL from environment variables:

// lib/queue.ts
import { Queue, Worker } from 'bullmq'
import IORedis from 'ioredis'

const connection = new IORedis(process.env.REDIS_URL, {
  maxRetriesPerRequest: null
})

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

For serverless deployments where Redis cost is prohibitive, use pg-boss against your existing DATABASE_URL.