Background: I'm creating a website that will deploy websites using firebase. The one-liner is that they fill out information and the web app deploys a website with that information. It's a Node app with react frontend and express backend. I plan to deploy this on firebase too but I'm not attached to this idea. I wrote an npm script that will create a project and deploy a site on the firebase project but it only works because I'm already logged in on my machine. Currently, it logs in through the web interface using OAuth2.0 and my google account. I cant find anything online on this. All my search results bring me to firebase's authentication feature.
Question: Are there alternative programmatic ways to login to firebase? If not, do you have any guidance on how I can accomplish this otherwise?
I think you're confused about what it means to be "logged in to firebase".
If you asking how to automate deployment with the Firebase CLI, without needing to sign in using a browser to authenticate your identity, then you should read the documentation about using the CLI with CI systems. You can sign in once manaully and get a token, then use that token on the command line to perform you deployment without having to manually sign in again.