app.yaml

runtime: nodejs
env: flex

# https://cloud.google.com/appengine/docs/flexible/nodejs/configuring-your-app-with-app-yaml
# This sample incurs costs to run on the App Engine flexible environment.
# The settings below are to reduce costs during testing and are not appropriate
# for production use. For more information, see:
# https://cloud.google.com/appengine/docs/flexible/nodejs/configuring-your-app-with-app-yaml
manual_scaling:
  instances: 1

resources:
  cpu: .5
  memory_gb: 0.5
  disk_size_gb: 10

handlers:
  - url: /
    static_files: client/build/index.html
    upload: client/build/index.html
  - url: /
    static_dir: client/build
# manual_scaling - Lock instances to 1 . using App Engine Flexible will create VM instances to serve from. If you want to lower your usage, you might restrict your App to just one 1 instance (probably not what you want in production, but perfect for in prototyping and development cases ).
# https://stackoverflow.com/questions/37381694/google-app-engine-how-to-correctly-deploy-an-app