To use JFrog Artifactory with the npm registry you just need to add the following to your build spec (seed.yml):

before_compile:
  - echo "registry=https://<ARTIFACTORY_SERVER_DOMAIN>/artifactory/api/npm/npm-repo/" >> ~/.npmrc
  - echo "_auth=<AUTH_CODE>" >> ~/.npmrc
  - echo "email=<YOUR_ACCOUNT_EMAIL>" >> ~/.npmrc
  - echo "always-auth=true" >> ~/.npmrc

Where, to get the AUTH_CODE you need to run the following:

$ curl -u<USERNAME>:<CREDENTIAL> https://<ARTIFACTORY_SERVER_DOMAIN>/artifactory/api/npm/npm-repo/auth

Here the CREDENTIAL can either be your password or your API key.

Also, YOUR_ACCOUNT_EMAIL is the admin email for your JFrog account. And ARTIFACTORY_SERVER_DOMAIN is the custom domain you’ve configured for Artifactory.