GAE = Google App Engine
Basic deploy flow:
https://github.com/HelperLine/gae-test-flask
Plain express.js
example from Google:
https://github.com/GoogleCloudPlatform/nodejs-docs-samples/tree/master/appengine/building-an-app/build
Official guide:
https://cloud.google.com/appengine/docs/standard/nodejs/mapping-custom-domains
Helpful description:
https://code.luasoftware.com/tutorials/domain-name/configure-dns-namecheap-for-google-app-engine-custom-domains/