It's common to install packages from multiple registries. For example, an organization may wish to install packages from @my-org from their own registry, while still using the official npm registry for other packages.

You can achieve this with a line in your .npmrc that looks something like this:

@my-org:registry=https://npm.pkg.github.com

With npm-api, the registry is hard-coded in lib/config.js. It does not look at .npmrc, and does not provide a way to manually override the registry location/add a second location.