DeployHQ build servers come with Node.js versions 8 through 25 pre-installed and selectable from the language version dropdown. If your project requires a specific version that isn't available in the dropdown, you can use the pre-installed NVM (Node Version Manager) 0.40.3.

Add the following commands to the beginning of your build command, replacing the version of Node as appropriate:

```bash
source /opt/nvm/nvm.sh
nvm install 21.6.1
nvm use 21.6.1
```

For example, to install and use Node.js 23.5.0:

```bash
source /opt/nvm/nvm.sh
nvm install 23.5.0
nvm use 23.5.0
node --version
npm install
npm run build
```

NVM is globally available at `/opt/nvm` and configured for use in build pipelines, so you don't need to install it.