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Day 19 - KM0 Mail: native sign-in, self-service registration, and your own domains

KM0 Mail no longer relies on external redirects: native login, one-minute registration, and self-managed custom domains from webmail.

Since we launched KM0 Email (see day 11), the mail stack has matured. The latest round of changes in km0-mail follows a simple idea: anyone should be able to have their own mailbox without depending on Gmail, without opaque panels, and without paid APIs.

Native sign-in, no detours

Signing in used to bounce through a separate authentication service. Now mail.km0digital.com asks for your email and password directly. OpenCloud / LDAP sign-in still exists, but as a secondary option for people who already have a cloud account.

We also improved the error messages: if credentials fail or the server does not respond, it now says so clearly and in your language (ES, CA, EN, DE), instead of a generic “Login failed”.

Registration in a minute

The /register page was stripped down: pick a username and password and get username@km0digital.com instantly. You verify the account from your own inbox. You can receive and read mail right away; to send, you first confirm the verification link. It is a simple defense against abuse, with no friction for the legitimate user.

Your own domain, self-managed

The big addition: custom domains without going through support. Inside webmail, under Settings > My domains, any user can:

  1. Add their domain (for example yourdomain.com).
  2. Publish the DNS records we show: ownership (TXT), MX, SPF, and DKIM.
  3. Click Verify and wait for propagation.
  4. Create name@yourdomain.com addresses with their own password.

Each domain signs its mail with its own DKIM, so deliverability does not hang on a single shared domain. The whole flow is self-service, in the style of the large providers, but on infrastructure we control.

No paid dependencies

None of this uses Google Workspace APIs, paid relays, or external verification services. It is self-hosted mail, on the same server Kilometer 0 already operates.

Closing

Mail went from “internal mailboxes” to a service anyone can use and extend with their own domain. To put it into practice, we wrote step-by-step guides: see the KM0 Mail tutorials or go straight to mail.km0digital.com. In day 20 we cover how those tutorials turned out.

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