Architecting Backpressure in Node.js Streams

Backpressure is the mechanism of signaling a data producer to slow down when the consumer's internal buffer is full, preventing memory exhaustion.

In Node.js streams, data is buffered in memory. If a Readable stream is faster than the Writable stream (e.g., reading a fast SSD and writing to a slow 3G network), the buffer will grow indefinitely until the process crashes. Handling backpressure involves monitoring the return value of stream.write(). If it returns false, the buffer is full (exceeded highWaterMark). The producer must pause until the drain event is emitted by the consumer. Using stream.pipeline() or .pipe() handles this automatically, but manual implementation is often required for custom complex architectures.