You’ll need to request the NPM registry url. The default is https://registry.npmjs.org but you can get it by running npm config get registry from the command line.
For specific packages the package url is https://registry.npmjs.org/<package_name> where the <package_name> is the package you need to download. e.g https://registry.npmjs.org/gulp but you’re better off requesting the base registry url if you are installing a number of packages which I suspect is the case for UX