Node.js, Express & HTTP
Trace requests, understand the runtime, and build reliable APIs.
How do I handle backpressure and large uploads?
Backpressure is a feedback mechanism that slows a producer when the consumer cannot keep up. Without it, incoming chunks may accumulate in memory even though the application is using streams. Node streams expose flow-control signals and utilities that help coordinate reading, writing, cleanup and errors.
What should I check for slow APIs, memory growth or intermittent 500s?
Slow responses, growing memory and 500 errors are symptoms, not root causes. A useful investigation connects each symptom to a specific route, instance, input or dependency. Comparing healthy and unhealthy requests often narrows the problem faster than changing settings blindly.
What if the event loop, DB pool or third-party API is stuck?
A stuck backend often means a shared resource is occupied or an operation has no effective deadline. The event loop, connection pool and external API each have different ways to become saturated. Identify which queue is growing before deciding whether to optimize work, cancel it, limit it or scale capacity.
Difficulty is an editorial estimate. Completion means you chose to mark a question as understood.