Authorization flow in a background job

I need to integrate with Altrusit, and sync Positions,Accounts etc in a daily basis job. Based on the flow diagram of Authorization you provide on you documentation, it looks like having an UI and User interaction its required. (referring to Step 1: Get an Authorization Code on https://altruist-open-api.readme.io/docs/authentication) Without this authorization code, I'm not able to get the token from step 2.

How do you suggest to implement this approach or maybe im missing something from the documentation?