Node.js is single-threaded by default (everything runs on the main thread), which is great for I/O tasks but bad for heavy computation (e.g., image processing, encryption, parsing large files). To offload heavy computational task we use Worker Threads in node.js.

• A Worker Thread is a way to run JavaScript in parallel on multiple threads (useful for CPU-heavy tasks).
• They share memory, but don’t spawn new processes.
• Ideal for CPU-bound tasks (math, compression, etc.) — not I/O-heavy work.
• API:
  • Run check: isMainThread
  • Send/Receive: parentPort.postMessage(), .on()
  • Input data: workerData
  • File path: Use new URL('./worker.js', import.meta.url) in ESM

• Node.js
• Express
• Node.js worker-thread module

# Clone the repo git clone https://github.com/rupachowrasia/nodejs-multithreading-worker-threads.git # Move into the project directory cd nodejs-multithreading-worker-threads # Install dependencies npm install # Run the app npm run start