nvm vs fnm: Faster Node Version Switching
nvm is the most widely used Node version manager, written in shell; fnm is a fast Rust alternative with quicker shell startup.
nvm manages Node versions through shell functions and a .nvmrc file and is installed nearly everywhere, but its shell sourcing slows terminal startup. fnm does the same job in Rust, starting much faster, supporting .nvmrc and .node-version, and switching versions on cd. Both pin Node per project; fnm trades nvm ubiquity for noticeably better speed.
| nvm | fnm | |
|---|---|---|
| Language | Shell | Rust |
| Speed | Slow shell startup | Fast |
| Config | .nvmrc | .nvmrc / .node-version |
| Auto-switch | Plugin / manual | On cd |
| Best for | Maximum ubiquity | Speed-conscious devs |
In CI
nvm works in CI but adds shell sourcing overhead per job; fnm installs and switches Node faster from a single binary. Both read .nvmrc so migration is easy. In practice many pipelines use setup-node, but for jobs that must honor a repo .nvmrc, fnm is the leaner option.
Speed it up
Cache the Node install directory and the package manager cache keyed on .nvmrc and the lockfile. Both run on CI runners; faster managed runners shorten the Node install and dependency steps.
The verdict
Wanting the most universally available tool with the largest community: nvm. Wanting fast shell startup and quick version switches from a single binary: fnm. fnm reads .nvmrc, so trying it alongside nvm is low risk.