Heroku: procfile

https://devcenter.heroku.com/articles/procfile Heroku apps include a Procfile that specifies the commands that are executed by the app on startup. You can use a Procfile to declare a variety of process types, including:

• Your app’s web server
• Multiple types of worker processes
• A singleton process, such as a clock
• Tasks to run before a new release is deployed

Examples

Rails

web: bundle exec rails server -p $PORT

Clojure

web: lein run -m demo.web $PORT

In case you have multiple buildpacks for the application you can ensure static rendering in procfile

web: bin/boot 

Related

• app.json
• Buildpack

See also

• Heroku, Heroku Review Apps, procfile, app.json, Heroku Flow, heroku login, heroku --help

https://elements.heroku.com/buildpacks/heroku/heroku-buildpack-static