Procfile

The Procfile is something that Heroku introduced and has been adopted as somewhat of a standard for expressing what commands are run to start an application. In the case of deplo.io you can use the Procfile to override the otherwise automatically generated web entrypoint that will be executed when starting your application.

For example, when trying to run a Docusaurus project on deplo.io, the following Procfile is needed as by default it would try to start a development server:

web: npm run serve -- -p $PORT

Other keys than web won't influence how your app is being run on deplo.io.