[herewulf]

That's a good question for which I couldn't find an answer on their site. They recommend getting in touch[1] for questions not answered. The lowest plan[2] allows 200 inbound messages per day which even including spam seems sufficiently high for a handful of inboxes.

The HN audience is more likely to be impacted by FOSS mailing lists and so that could be a legitimate concern.

In any case, their key advantage over competitors is not charging by user and allowing unlimited domains.

[1]: https://migadu.com/contact/ [2]: https://migadu.com/pricing/