Clustering spawns multiple OS-level processes ideal for I/O-bound tasks like HTTP servers, while Worker Threads run multiple threads within a single process, sharing memory, and are ideal for CPU-bound tasks like data processing or computation.

Both Clustering and Worker Threads allow Node.js to use multiple CPU cores, but they work at different levels and solve different problems. Clustering is best for scaling network servers, while Worker Threads are best for parallelizing heavy computations without spawning expensive OS processes.

Clustering Characteristics

1
Each worker is a separate OS process — higher memory overhead per worker
2
No shared memory — complete isolation between processes
3
Ideal for HTTP servers, API services, and I/O-bound workloads
4
Communication via IPC with JSON message serialization
5
A process crash is isolated — one worker dying does not affect others
6
Available since Node.js v0.8

Worker Threads Characteristics

1
Threads within the same process — lower memory overhead
2
Can share memory via SharedArrayBuffer and Atomics
3
Ideal for CPU-intensive tasks: image processing, cryptography, ML inference
4
Communication via MessageChannel or postMessage
5
Thread crash can potentially affect the entire process
6
Available since Node.js v10.5 (stable in v12)

Worker Threads for CPU-Bound Task