I have been building an app with Node / Express and I want to add billing to the app, but I am confused by how the documentation is laid out.
Would I follow the instructions under Charge A Fee Using The Billing API because this is under Build a Shopify App with Node and React and their does not appear to be a dedicated article for Build a Shopify App with Node and Express (unless I am overlooking it).
Is there an example of this in the Shopify Git Hub Repo? I may be missing it when looking.
We don't have language specific guides, but there are language agnostic guides that run you through the features of the Billing API which you can access here.
If you have specific questions in regards to implementing your billing model with Node and Express, I would encourage you to post them on the forums to get help from the community.