The distinction between V8 helpers and the libuv pool is useful. One caveat for readers: the exact startup thread count can vary with Node/V8 versions, platform and runtime flags, so seven is an observation rather than a portable guarantee. Also, single-threaded JavaScript can still have logical races across await boundaries. For a payment handler, for example, checking a balance and updating it in separate steps still needs a database transaction or another concurrency safeguard.