No SMTP or IMAP as it’s an E2EE service and unlike Proton they don’t (yet anyway) have a “bridge” service. You get to use your own domain, a handful of aliases, and a generous amount of storage all on the free plan with higher limits on the paid plans.
Anyone looking for standard mail protocol support and gobs of storage for free/cheap and who are cool with a very non-sexy 90s web UI, would do well to check out the European provider mail.ee . They’ve been reliable for me over the past year or so though I’m not exactly a high-volume customer.
Check out spamgourmet.com . Fresh 90s UI, unlimited aliases using their domains (ex: xoxy.net), and completely free. It’s not an email service though, they only do forwarding.