If your aliases are on the provider's domain, they stop working — all of them, at once. Addresses ending @duck.com, @mozmail.com, @icloud.com or @simplelogin.com depend on that company continuing to operate and on you continuing to be their customer. If your aliases are on a domain you own, you point the domain at a different mail service and every address keeps working. The addresses outlive the provider.
Why this question comes up late
It doesn't feel important on day one. You're comparing free tiers, mask limits, browser extensions. Whether the addresses survive a provider change is an abstraction.
Three years and two hundred aliases later it stops being abstract. Those addresses are now the contact of record for your bank, your insurer, your utilities, your government correspondence and every shop you've used. They're the addresses password resets go to. At that point, "what happens if this provider stops" is a question about whether you can still get into your own accounts.
Rented namespace versus owned namespace
Every alias lives on a domain. The only question is who controls it.
| Event | Aliases on the provider's domain | Aliases on your domain |
|---|---|---|
| Provider shuts down | Every address stops working | Repoint the domain; addresses keep working |
| You want to switch provider | Every address must be changed at every service | Change the routing; addresses unchanged |
| Provider raises the price | Pay, or re-address everything | Move the domain elsewhere |
| Your account is suspended | Every address stops working | Repoint the domain |
| Provider drops the free tier | Aliases beyond the new limit may stop | Not applicable |
| You stop paying | Varies — some keep existing aliases alive, some don't | Domain is yours until it expires |
The right-hand column has one failure mode: you forget to renew the domain. That's a real risk and it's worth taking seriously — turn on auto-renew and keep the registrar's billing details current. But it's a risk you control, which is a different category from a risk somebody else controls.
Is this a realistic worry?
It's worth being measured about this. Apple, Mozilla, DuckDuckGo and Proton are all substantial organisations, and none of them is likely to vanish next week. Overstating the danger would be exactly the kind of scare-selling this category is full of.
But shutting down isn't the only way to lose the addresses, and it isn't the most likely one. The realistic scenarios are ordinary:
- A free tier gets restructured, and the limit now sits below the number of aliases you have.
- A product is discontinued while the company continues — a routine event in tech.
- You want to leave for reasons of price, features, or policy.
- Your account is locked over a billing problem or an automated flag.
In every one of those, the question is the same: are the addresses yours, or theirs?
What migration actually costs
Say you decide to move two hundred aliases off a provider domain. The work is not moving the aliases — it's updating the address on two hundred accounts, each with its own settings page, each usually requiring a confirmation email to the new address, and some requiring a support ticket. Any account you can't get into because the reset goes to the old address becomes a separate problem.
With your own domain, that migration is a DNS change. The addresses never change, so no account needs updating at all.
The honest cost of owning the namespace
- Money. A domain costs roughly the price of a couple of coffees a year for a common extension. DuckDuckGo Email Protection costs nothing.
- Setup. DNS records, once. Ten minutes if the service walks you through it, longer if you've never seen an MX record.
- Renewals. Your responsibility now.
- A little anonymity. A domain is registered to someone — use WHOIS privacy — and a domain only you use is a consistent identifier across services. A shared provider domain hides you in a crowd; your own domain does not.
If those trade-offs don't appeal, a provider-hosted alias service is a perfectly sensible choice, and we say so in our comparison with DuckDuckGo Email Protection.
How to decide
A rough rule: the more accounts depend on an address, the more the namespace matters.
- Using aliases for a handful of newsletters? Rented is fine. Losing them costs nothing.
- Routing your financial, medical and government correspondence through them? Own the domain. The cost of being locked out dwarfs the cost of the domain.
Both SimpleLogin and Don't SPAM Me support your own domain. The distinction between them is elsewhere — see the comparison. And if you're still deciding whether per-service addresses are worth the effort at all, start with email aliases explained.