1. #1

   Seniorstreamsperformance

   What is backpressure and how do you handle it?

   Backpressure is when a writable stream can’t consume data as fast as it arrives; honour the write() return value or use pipeline to pause the source.

2. #2

   Seniormemorydebugging

   How do you diagnose a memory leak in a Node.js service?

   Watch heap growth over time, capture heap snapshots and diff them to find retained objects, and inspect common culprits like caches, listeners, and closures.

3. #3

   Seniorscalingdeployment

   How do you achieve zero-downtime deploys with clustered Node processes?

   Roll workers one at a time: start new instances, wait until healthy, drain and gracefully shut old ones so in-flight requests finish before exit.

4. #4

   Senioreventsarchitecture

   What are best practices and pitfalls with EventEmitter?

   Always handle the error event, remove listeners to avoid leaks, watch the max-listeners limit, and prefer async iterators for stream-like consumption.

5. #5

   Seniorcachingperformance

   What caching strategies improve a Node.js API’s performance and cost?

   Layer caching: in-memory for hot data, Redis for shared state, HTTP caching headers at the edge, and cache expensive computed or third-party results.

6. #6

   Seniorresilienceerrors

   How do you make a Node service resilient to downstream failures?

   Use timeouts, retries with backoff and jitter, circuit breakers, bulkheads, and fallbacks so one failing dependency doesn’t cascade into an outage.

7. #7

   Seniorobservabilitymonitoring

   What does observability for a Node.js backend involve?

   Structured logs, metrics, and distributed tracing — the three pillars — plus correlation IDs to follow a request across services.

8. #8

   Seniornativeperformance

   When would you reach for native add-ons or WebAssembly in Node.js?

   For performance-critical or system-level work beyond JS’s reach — heavy computation, existing C/C++ libraries — via N-API native add-ons or WebAssembly modules.

9. #9

   Seniorevent-loopinternals

   What is the difference between process.nextTick and setImmediate?

   process.nextTick callbacks run before the event loop continues (after the current operation); setImmediate runs in the check phase, after I/O callbacks.

10. #10

    Seniorarchitecturemicroservices

    What are the trade-offs of a microservices architecture with Node.js?

    Microservices give independent scaling and deploys but add network latency, distributed-system complexity, and operational overhead — often premature for small teams.