• Java 1.8 (not later, as Google App Engine doesn't yet support it).
• Google Cloud SDK.
• Maven.
• Ruby 2.5 or later with bundler.
• An HTTP client such as Postman or curl.

1. Start dummy Origon mailer:
   • Clone andersblehr/origon-mailer.
   • Comment out lines 24-29 in mailer_controller.rb.
   • Install dependencies: bundle install
   • Start dummy mailer: rackup -p 4567
2. In another terminal window, start Google Cloud Datastore emulator:

   $ gcloud beta emulators datastore start
   

3. In a third terminal window, start the Google App Engine development server:

   $ export DATASTORE_EMULATOR_HOST=localhost:8081
   $ mvn appengine:run
   

All Origon's backend components are now up and running and you can issue HTTP requests via Postman or curl, or by running the iOS app in the iOS Simulator.