| 1 | What is a cron job, and how would you schedule recurring background tasks in a Node.js application using node-cron or BullMQ's repeatable jobs? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 2 | How do you implement graceful shutdown for a Node.js background worker process to avoid losing or corrupting in-progress jobs? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 3 | What is a background job in the context of a Node.js web application, and why can't long-running work simply happen inside a request handler? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Beginner |
| 4 | What is job idempotency, and why is it critical when designing background job processing? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 5 | How would you track and expose the progress of a long-running background job to the client that requested it? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 6 | What is the difference between a message queue (like RabbitMQ) and a job queue (like BullMQ), and when would you choose one over the other? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 7 | What is the difference between a delayed job and a scheduled (repeatable) job in a Node.js job queue? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Beginner |
| 8 | How does BullMQ (built on Redis) implement a job queue in Node.js, and what are its core building blocks? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 9 | What is job concurrency in a worker process, and how do you configure it safely in BullMQ? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 10 | What are the trade-offs of using an in-memory job queue (like a simple array-based queue) versus a persistent, Redis-backed queue? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 11 | What is a 'stalled' job in BullMQ, and what causes it? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Intermediate |
| 12 | What is a dead-letter queue (DLQ), and how should a Node.js job-processing system use one? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 13 | How do you implement job prioritization in a Node.js queue system, and when is it necessary? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 14 | What is job de-duplication in a queue system, and how would you prevent the same logical job from being enqueued multiple times? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 15 | How do you implement rate-limited job processing so a Node.js worker doesn't exceed a downstream third-party API's request limits? Node.js › Background Jobs & Queues | Node.js | Background Jobs & Queues | Advanced |
| 16 | How would you publish and consume messages using RabbitMQ in a Node.js application via the amqplib package? Node.js › Message Queues (RabbitMQ & Kafka) | Node.js | Message Queues (RabbitMQ & Kafka) | Intermediate |
| 17 | What is the difference between message acknowledgment modes (auto-ack vs manual ack) in a message queue, and why does manual ack matter for reliability? Node.js › Message Queues (RabbitMQ & Kafka) | Node.js | Message Queues (RabbitMQ & Kafka) | Intermediate |
| 18 | Why should sending an email typically happen in a background job rather than synchronously within an HTTP request handler? Node.js › Email & Notifications | Node.js | Email & Notifications | Intermediate |
| 19 | How would you implement idempotent notification sending to avoid sending a duplicate email if a background job is retried? Node.js › Email & Notifications | Node.js | Email & Notifications | Advanced |
| 20 | What is Nodemailer, and how does it let a Node.js application send emails via SMTP? Node.js › Email & Notifications | Node.js | Email & Notifications | Beginner |
| 21 | What is the difference between the CMD and ENTRYPOINT instructions in a Dockerfile for a Node.js application? Node.js › Docker & Deployment | Node.js | Docker & Deployment | Intermediate |
| 22 | How would you send a push notification from a Node.js backend to a mobile app using Firebase Cloud Messaging (FCM)? Node.js › Email & Notifications | Node.js | Email & Notifications | Intermediate |
| 23 | How would you test that a Node.js application correctly sends emails without actually sending real emails during automated tests? Node.js › Email & Notifications | Node.js | Email & Notifications | Intermediate |
| 24 | Why should CPU-intensive media processing like image resizing or video transcoding typically not run directly inside an Express request handler? Node.js › File Uploads & Media Processing | Node.js | File Uploads & Media Processing | Intermediate |
| 25 | How would you implement a concurrency-limited task queue in Node.js to process many async tasks without overwhelming a downstream resource? Node.js › Async Patterns | Node.js | Async Patterns | Advanced |
| 26 | What is auto-scaling, and what metrics commonly trigger scaling decisions for a Node.js service running in the cloud? Node.js › Cloud & DevOps | Node.js | Cloud & DevOps | Advanced |
| 27 | What is the WorkerData option when creating a Worker, and how does it differ from communicating via postMessage() after creation? Node.js › Clustering & Worker Threads | Node.js | Clustering & Worker Threads | Advanced |
| 28 | How do you properly handle process signals (SIGTERM) inside a containerized Node.js application to support graceful shutdown? Node.js › Docker & Deployment | Node.js | Docker & Deployment | Advanced |
| 29 | How would you design a multi-channel notification system in Node.js that can send the same logical notification via email, SMS, or push depending on user preference? Node.js › Email & Notifications | Node.js | Email & Notifications | Advanced |
| 30 | How would you implement rate limiting or throttling for outgoing notifications to avoid overwhelming users or violating a provider's sending limits? Node.js › Email & Notifications | Node.js | Email & Notifications | Advanced |
| 31 | How would you handle email delivery webhooks (bounces, complaints, opens) sent from a provider like SendGrid back to a Node.js application? Node.js › Email & Notifications | Node.js | Email & Notifications | Advanced |
| 32 | How would you generate a video thumbnail in Node.js using ffmpeg via a library like fluent-ffmpeg? Node.js › File Uploads & Media Processing | Node.js | File Uploads & Media Processing | Advanced |
| 33 | How would you scan uploaded files for malware before accepting them into permanent storage in a Node.js application? Node.js › File Uploads & Media Processing | Node.js | File Uploads & Media Processing | Advanced |
| 34 | How would you implement a distributed lock using Redis to coordinate access to a shared resource across multiple Node.js instances? Node.js › Caching with Redis | Node.js | Caching with Redis | Advanced |
| 35 | How do you correctly handle OS signals like SIGTERM and SIGINT in a Node.js application to implement graceful shutdown? Node.js › Global Objects & the process Object | Node.js | Global Objects & the process Object | Advanced |