I need to make sure alcohol isn't advertised to underage users or in countries / regions where alcohol is illegal.
Ideally using MaxMind geo codes but I'm sure I could map from any geo system.
One option is to use a Github repo (fork your own) that other users can contribute to, which will help keep it up to date.
Although for regulatory purposes, this may not be sufficient. Also, this is a really nuanced topic, so may be tough to capture with 100% coverage.
For example, Switzerland:
18 for spirits 16 or 18 for beer and wine depending on the Canton
Any csv can be turned into a json API, although this example is a bit overkill.