Can I use mediawiki-core JS library (mediawiki.*) outside MediaWiki's front-end environment? If possible, what do I need to configure before using it (like to be able to execute a POST request with token)?
Topic on Talk:ResourceLoader/Core modules
Executing POST requests with tokens doesn't need the mediawiki.* library.
Use native XMLHttpRequest objects from JavaScript, or utility libraries like jQuery against the MediaWiki api.