@julian You could totally skip the API. Just go to your Mastodon instance profile settings and request an export of your posts.
Then have Hugo or something else read that export and build a site with it.
@julian The downside (hence why I didn't do it) is that it can't be automated. I didn't want to have to request and export, download and import it to the other system manually.
Using the Mastodon API and GitHub Actions running every day, I know my archive is fresh every morning.