Node memory keeps growing. How do I investigate?

Short explanation:

Growing Node memory can be normal temporary allocation, retained JavaScript objects, native buffers or another process-level resource. A leak is suggested when unnecessary retained memory continues to grow across comparable workloads and garbage-collection cycles. Heap size and total process memory are related but not identical measurements.

Key points:

• Compare heap snapshots and memory after garbage collection.

• Check retained objects, listeners, timers, unbounded caches and buffers.

• Remove the retention source and rerun a sustained workload; a restart only buys time.

• Compare heap usage, external memory and RSS to avoid assuming every growth source is a JavaScript object.

• Capture diagnostic snapshots carefully because creating them can affect a busy process, then inspect retention paths.

Interview point:

• Identify what keeps the data reachable and demonstrate that growth stabilizes after the fix.