No daemon, on purpose

Sep 10, 2026

Nx runs a daemon by default. Turborepo shipped one and, as of 2.10, is deprecating it. Both exist for the same reason: a warm run needs to know what changed since the last one, and walking the filesystem to find out is slow. So a background process watches the tree and keeps the answer ready.

vx has no daemon and will not grow one. Here is the reasoning, and what replaced it.

What a daemon costs

A daemon is a second copy of the truth. It holds a model of the tree that is correct exactly as long as every change went through a filesystem event it received and processed. The failure modes are familiar to anyone who has typed nx reset: a socket left behind by a crashed process, a stale graph after a branch switch, an event dropped on a busy machine, a watcher that started after the edit. Each one turns a fast answer into a wrong one, and “wrong” for a build cache means a stale hit under a green check.

It also costs the thing it is meant to save. A daemon must be started, must warm up, must be restarted after an upgrade, and holds memory for the whole session. The first run of the day pays a cold start either way.

What replaced it

The question a daemon answers is “which files’ hashes do I need to recompute?” vx made the recomputation cheap enough that the question stopped mattering:

The hashes are in git’s index. One git ls-files -s returns the file list and every clean file’s blob id. A concurrent git status names the dirty ones. A clean tree of thousands of files is keyed with no file reads at all (the details).
Config evaluation is cached where it is provably safe, keyed by the git blob ids of the import closure, and evaluated live where it is not.
The graph algorithms are bitsets, so building priorities over 3,270 tasks is milliseconds, not seconds.
A warm hit on a current tree is N stats and zero writes, because strict output ownership means vx knows what the tree should contain.

The result is a fully cached run of 3,270 tasks in 510ms with no process left behind, against Turborepo’s 760ms and Nx’s 3.59s. On solidjs/solid, Turbo measured with --no-daemon so both tools pay discovery, vx’s no-op run is 51 ms to Turbo’s 95 ms. Turbo’s daemon would close part of that gap. vx has nothing to turn on.

The invariant, stated plainly

There is exactly one source of truth for what a task depends on: the working tree as git sees it, read fresh on every run. There is no staleness window because there is no second copy that could be stale. vx run in a terminal, in CI, in a container, on a machine whose watcher limits are exhausted, all take the same path and give the same answer.

That is worth more than a daemon’s best case, and it costs less than a daemon’s average case.