At KDE, we have to do fairly complex invoicing to recipients in many different jurisdictions (as a non-profit having donors and organizing events all over the globe).
We also wrote a web app (using quart and hypercorn) for this that generates PDFs (it's part of our internal financial dashboard that does a lot of other things as well). But ours runs the jobs on the backend, and uses luatex via latexmk. This internally uses scrlttr2 as well.
We also wrote a web app (using quart and hypercorn) for this that generates PDFs (it's part of our internal financial dashboard that does a lot of other things as well). But ours runs the jobs on the backend, and uses luatex via latexmk. This internally uses scrlttr2 as well.
Screenshot: https://mero.ng/i/GKeVmAnd.png