https://medium.com/the-node-js-collection/making-your-node-js-work-everywhere-with-environment-variables-2da8cdf6e786 https://www.twilio.com/blog/2017/08/working-with-environment-variables-in-node-js.html What, why, when, how. the docs: https://nodejs.org/api/process.html#process_process_env