What are the other heroku environment variables?
The following command will display all of the environment variables, not just those visible from heroku config:
heroku run printenv
heroku config does not show PORT. So, it's incomplete if you need everything. This will create a one-off dyno and show everything.
From here: https://devcenter.heroku.com/articles/getting-started-with-nodejs#console
Run a console in a one-off dyno, then at the > prompt, type "console.log(process.env)":
$ heroku run nodeRunning `node` attached to terminal... up, run.4778> console.log(process.env... ){ BUILDPACK_URL: 'https://github.com/MichaelJCole/heroku-buildpack-nodejs.git#wintersmith', TERM: 'xterm', SENDGRID_USERNAME: 'unicorns@heroku.com', COLUMNS: '80', DYNO: 'run.4778', PATH: '/app/bin:/app/node_modules/.bin:bin:node_modules/.bin:/usr/local/bin:/usr/bin:/bin', PWD: '/app', PS1: 'fairydust', LINES: '22', SHLVL: '1', HOME: '/app', SENDGRID_PASSWORD: 'ponies', PORT: '52031', _: '/app/bin/node' }undefined
The command is
heroku configYou can read more here https://devcenter.heroku.com/articles/config-vars