Howard Miller

Oh you meant *web service* API? No... no such thing that I am aware of. You'll need to write your own.

FWIW, I am in the middle of a very big project for a grading front-end for Moodle. The UI is entirely in Vue.js, and the back-end is a Moodle local-plugin. I imagine that this is something similar to your project. I have not been able to use any core web service calls at all. I think I've written around 30 new web service functions... so far.

core_string_manager_standard::get_list_of_countries()

Good point... moved.

My development environment uses Docker (nginx, php-fpm, Mariadb and Redis) and works fine without any particular configuration. Noting the lack of styling on your example page - before we go any further - have you got nginx configured properly? See Nginx (it being in a container is irrelevant).

Failing that, you're going to have to give us a detailed description of your setup.

Bear in mind that there's an "official" docker-compose script for developers here, https://github.com/moodlehq/moodle-docker. I found it way too complicated for my needs, so created my own but you might find it useful.