Question

I don’t want to commit the username/password combo for an e-mail server to Git, as the source code is made public. Is there a way to change it on Heroku itself?

Answer 1

https://devcenter.heroku.com/articles/config-vars

The traditional approach for handling such config vars is to put them under source – in a properties file of some sort. This is an error-prone process, and is especially complicated for open source apps which often have to maintain separate (and private) branches with app-specific configurations.

A better solution is to use environment variables, and keep the keys out of the code. On a traditional host or working locally you can set environment vars in your bashrc. On Heroku, you use config vars.

Use the Heroku CLI’s config, config:add, config:get and config:remove to manage your config vars: