BullMQ and p-queue occupy different niches in the JavaScript backend ecosystem. BullMQ is a production-grade, Redis-backed distributed job queue designed for persistent task management across multiple processes and servers. It handles complex workflows with retries, priorities, scheduling, and monitoring. In contrast, p-queue is a lightweight, in-memory promise concurrency limiter that controls how many async operations run simultaneously within a single process—no persistence, no Redis, no distribution.
This comparison matters because developers often conflate general-purpose queues with concurrency limiters. BullMQ targets teams building scalable microservices, background job processors, or any system requiring durable task queues with horizontal scaling. P-queue serves developers who need simple rate limiting for API calls, controlled parallel processing in scripts, or browser-based async management without external infrastructure. Choosing the wrong tool means either over-engineering simple tasks or under-delivering on reliability requirements.
Choose BullMQ when you need job durability, distributed processing, or any form of persistence. If your system spans multiple servers, requires retry logic, handles critical background tasks that cannot be lost, or needs job scheduling beyond immediate execution, BullMQ is the only viable option here. The Redis requirement is a feature, not a burden—it provides the foundation for reliability that production systems demand. The complexity pays for itself once you need even one advanced feature like delayed jobs or failure recovery.
Choose p-queue for in-memory concurrency control where job loss on crash is acceptable. This includes rate-limiting third-party API calls, controlling parallel file operations in build scripts, managing browser fetch concurrency, or any scenario where you're orchestrating promises in a single process without durability needs. If adding Redis to your stack feels like overkill, it probably is—p-queue solves the immediate problem without infrastructure overhead. Don't use p-queue if jobs must survive restarts or run across multiple processes; don't use BullMQ if you're just limiting concurrent HTTP requests in a one-off script.