Mail that keeps
its own secrets.

What you get

A mailbox, sealed where it sits

• IMAP 993 (TLS) and SMTP 587 (STARTTLS) — any client: our sealed apps, Thunderbird, Apple Mail, a phone.
• Your own domain — point its MX at us; each domain is US$5 a month. Up to 5 addresses on it, named by you.
• Encrypted at rest — the mail volume is a LUKS-encrypted disk on this server; the passphrase is sealed inside the CUBE store, and the mail volume refuses to mount for postfix or dovecot unless someone unlocks it first.
• TLS hardened — TLS 1.2 and 1.3 only, ssl_dh + modern ciphers, delivery TLS logged; opportunistic SMTP TLS everywhere it is offered.
• MTA-STS and TLS-RPT — we publish a strict inbound policy for mail.domain and receive reports, so downgrade attacks against our MX are visible and refused.
• No read receipts, no tracking pixels, no ads — we do not profile your mail.
• Remote hold, optional — with the relay on, sealed mail can wait on our relay while your app is away (7 days by default, 30 at most) and is filed the next time the app syncs; turning hold off drains anything left into the mailbox.

Honest limits: the server sees plaintext mail while it delivers it — that is how every hosted inbox on earth works. If you want the server to store no readable body for you at all, that is the sealed-relay tier — switched on from inside CUBED-mail or CUBE-Contact and included with either app.