One licence per server. Never per mailbox.

A Linux VPS with Docker, a domain, and the ability to set DNS records. One command installs everything — Postfix, Dovecot, Rspamd, Postgres, the control plane and the webmail — as a Docker Compose bundle. The install guide is the whole of it.

You also need a provider that does not block outbound port 25, and a static IP with reverse DNS you control. That is a hosting question rather than a MailDock one, but it is the thing that most often decides whether self-hosted mail works.

Your incoming mail never does. From 0.13.0 a lapsed licence switches off extras in stages, and never touches the mail you receive:

• Days 0–30: everything works. The admin panel shows a countdown, and the server emails its owners.
• From day 30: new domains, mailboxes, AI features, new sending tokens and starting migrations are refused. Everything else keeps working.
• From day 60: the admin panel is read-only. Security actions (suspending a mailbox, resetting a password), the licence page and backups stay open.
• From day 90, and only once the licence period has ended without renewal (or 90 days after setup on a server never licensed): mail to outside addresses is refused. Receiving and reading mail, and delivery between your own mailboxes, carry on; so do forwards, auto-replies and password-reset links.

The 30 days run from the end of the subscription, or from the server’s last check-in with our licence server if it cannot reach us; a licence key installed on another machine is limited at once, until it is transferred. A server that cannot reach us never loses its outgoing mail: that kind of lapse stops at the read-only admin panel. Renewing restores everything as soon as the renewed key reaches the server (at once if you install it), and cancelling expires the licence at the end of the period you paid for; cancelling never revokes one.

Per server, per year. The tier sets a cap on mailboxes and domains — Starter is 10 mailboxes on 1 domain, Enterprise is uncapped — but you are never billed per seat, and adding a mailbox inside your cap costs nothing.

If you outgrow a tier, you change plan in the billing portal and the new limits arrive with the next licence heartbeat.

No. Instead, a first annual licence carries a 30-day money-back guarantee: if it is not right for you, tell us within 30 days of the charge and we refund it in full, however much you used it (the refund policy has the details).

The documentation is public, so you can read exactly how it installs and what it does before you buy.

Yes, and usually yourself, without contacting anyone. A licence is bound to one server at a time. When that machine changes — a rebuild, a restore onto new hardware, a new hostname — you move it from the new server: Licence → Move this licence to this server in the admin console, or mailctl license transfer. There is nothing to do on the old machine; the key installed on the new one is the proof.

Two cases come to us instead, and we move the licence for you: a key that is lost, and a key installed as it was first issued on a second server after another one had already claimed it. The admin console and mailctl license status say when that has happened — Another server has claimed this licence — and we issue a key for the server you mean to keep. If both should run, each needs its own licence.

That is deliberate: rebuilding a VPS is a normal Tuesday, and a licence that turns a rebuild into a support ticket is a licence that punishes good practice.