Your address
The bit after the @ sign.
One shared British .uk domain, not one registered per account — fewer things to fail.
03 — What we are building
A standby mailbox that stays ready without anyone touching it.
Dart Mail is a second account, held in reserve. It is not a replacement for Microsoft 365 or Google Workspace and it is not a migration — it stands ready in the background, and takes the traffic on the day your everyday mail cannot.
It is a second account, not a move. Keep your existing mail exactly where it is. We hold a parallel mailbox for each of your people, on named UK infrastructure, with your dartmail.uk address already configured and waiting. Nobody signs in to it in the ordinary course of business, and during peacetime live traffic is capped at 10 messages a month — enough to prove it works, not enough to become a second inbox. Failover lifts that cap automatically.
Sign-in stays in the country. Your own directory, your own tokens, no round trip to an identity provider in another jurisdiction.
Certificates stay under UK control. We issue from a name-constrained UK trust anchor — a certificate authority cryptographically restricted to the dartmail.uk namespace, so it can never be used to impersonate anybody else, even if it were stolen.
A standby mailbox nobody ever touches is just a liability with a login page.
So instead of sitting completely idle, Dart Mail allows a small amount of real traffic during ordinary operation — up to 10 messages a month. Enough for you to prove to yourself that sign-in, delivery and certificates all still work, without it becoming a second inbox nobody remembers how to use.
What crosses the water, and what does not
MailboxA standalone dartmail.uk mailbox on UK infrastructure, ready when you are.
Sign-inYour directory and token issuance run on the same UK infrastructure.
TrafficCapped at 10 messages a month in peacetime; unlimited once failover activates.
CertsName-constrained UK anchor, restricted to the dartmail.uk namespace.
ExternalMail to and from abroad still crosses the seabed. Nothing we build changes that. It queues.
The directory that finds you
The internet's phone book.
Answered by machines standing in Britain, not abroad.
The computers holding your mail
Real machines in real buildings.
Named British datacentres, under British law, encrypted at rest.
The ID cards that prove it is you
The certificate behind the browser padlock.
Renewed in Britain, so they hold when the office abroad cannot be reached.
Sign up
A standalone service — there is no existing domain to connect and nothing to install. We provision your dartmail.uk mailbox and it is ready to use.
Prove it works
Send up to 10 messages a month through it — to yourself, to a colleague, however you like. Enough to know sign-in, delivery and certificates are all still working.
The day you need it
Sign in and start sending from your dartmail.uk address directly — there are no MX records to change. Internal mail flows. External mail queues until Britain reconnects.
What we are not claiming
- We cannot keep the internet up. If the cables go, most of what you use goes with them. We are solving one problem: your mail, and the sign-in and certificates it rests on.
We cannot guarantee uptime, and other third party services may fail between your computer screen and your recipients mailbox. With Dartmail you are just making an attempt to build some resilience into that flow. - This is insurance, not a mail system. Dart Mail will not be as good as Microsoft 365 on an ordinary Tuesday, and it is not trying to be. It has one job, on one bad day.
Therefore, during normal operation - the service can only send a small number of test mail. It comes into full use, should traditional mail services fail due to sabotage of undersea cabling.Let - Overseas mail will not get through. UK based mail may not either. Nobody can route around a severed cable. It goes without saying that overseas mail will most likely be unable to reach mainland Britain.
But similarly, the internet is a partchwork of services that interlink to provide the overall online platform that we use each day. There are unknown other services that may block the overall service from working.
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