Yes — you can connect a domain you already own instead of registering a new one through Maildoso. Bring-your-own domains have no registration fee, but each one still takes up a domain slot on your plan.
Before you start
Connecting replaces the domain's DNS. Maildoso takes over the nameservers and rewrites the MX, CNAME and TXT records of every domain you connect, so any email or other service currently running on it will stop working. Only connect domains that are not in active use.
Domains registered through Cloudflare Registrar aren't supported — you won't be able to complete the nameserver step. See the Cloudflare section below.
How to connect your existing domains
Open Domains in the left menu and click Connect existing domains at the bottom of the page (or use Home → Quick actions → Add domains → Connect existing).
Under What mailboxes will you create on these domains? choose Maildoso (standard SMTP mailboxes) or Google Workspace. A domain stays linked to the provider you choose.
Upload a CSV file with your domain names: up to 100 domains, one column, one domain per row, without
http://,https://orwww.(a CSV template is available on the page). Click Verify domains.Review domain availability, select the domains to connect and click Connect — we generate two dedicated nameservers for each domain.
Copy the nameservers (one by one or as a CSV) and set them at your registrar within 24 hours — see the registrar steps below. After 24 hours they expire and need to be regenerated (Domains → Bulk actions → Regenerate NS).
Once the change is detected, the domain activates automatically, usually in about 2 hours.
You can also add external domains via the API — your API token is under your account email (top right) → Settings → General. Domains waiting for nameservers can be downloaded from the Domains page with Export CSV → Awaiting NS Domains Only, and all your external domains with Export CSV → All External Domains.
Nameserver rule: set only our two nameservers at your registrar — nothing else. Extra or leftover nameservers (or none at all) stop us from generating DNS for the domain and it won't work. We manage all DNS for the domain (MX, SPF, DKIM, DMARC) ourselves — see How DNS works on your Maildoso domains.
Setting the nameservers at your registrar
The exact steps vary by registrar. In every case, change the nameservers at the registrar level (not just DNS records inside a DNS provider), choose the "custom nameservers" option, remove any leftover entries, and enter the two nameservers from your Maildoso dashboard exactly as shown.
GoDaddy: My Products → Domains → Manage All → select the domain → DNS / Manage DNS → Nameservers → Change → Enter my own nameservers → paste ours → Save.
Squarespace Domains: Settings → Domains → select the domain → DNS Settings → in Nameservers, switch from Squarespace's defaults to Custom nameservers and enter ours.
Spaceship.com: open the domain from your domain list → DNS / Nameservers → choose custom nameservers instead of Spaceship's defaults → enter ours and save.
Namecheap and others: look for the domain's Nameservers setting and select the custom option.
Nameservers match but the domain is still "Awaiting NS"
Nameserver changes need time to propagate — from a few minutes up to 24–48 hours depending on the registrar, even if the values already look correct when you check them. Before contacting support:
Check there are no leftover or duplicate nameserver entries at the registrar (some registrars keep old ones unless you explicitly remove them).
Confirm you edited nameservers at the registrar, not just records in an existing DNS provider (changing records in Cloudflare's DNS panel doesn't help if the registrar-level nameservers still point elsewhere).
Wait for propagation before re-checking, and avoid repeated changes — most cases resolve on their own within a day.
Still stuck after 24–48 hours with correct nameservers? See My domain shows "NS Not Set" (it also covers DNSSEC, which can block delegation even when the nameservers look correct) and contact support with the domain name. Hold off on creating mailboxes until the domain is fully connected — once it is, see Setting up domains and mailboxes.
Domains registered through Cloudflare Registrar
Domains registered through Cloudflare Registrar are locked to Cloudflare's own nameservers and can't be pointed to ours, so they can't be connected as-is — if you try, they typically get stuck at "NS Not Set". A domain that merely uses Cloudflare's DNS but is registered elsewhere is fine. Your options:
Transfer the domain to a registrar that allows custom nameservers, then connect it and add our two nameservers.
Use a domain registered elsewhere, or register a new domain through Maildoso.
Ask us to review your case — send us the domain names and we'll confirm the next step.
.de domains
.de can't currently be registered through Maildoso, because the registry requires KYC verification of the registrant. Connecting a .de domain you already own works normally — register it yourself at a registrar that supports .de, then connect it here as an external domain. See Can I register .de domains through Maildoso?
Re-adding a domain you previously removed or transferred out
If a domain was connected to Maildoso before, was later removed or transferred to your own registrar, and adding it back as an external domain fails even though it works fine elsewhere, our side usually still has a stale record for it. Contact support with the domain name and roughly when it was removed or transferred — we'll clear the old record so it can be reconnected.