Switzerland does not demand a confirmation email. Germany effectively does. Here is the difference, and why I still turn double opt-in on for every Swiss shop.
Double opt-in (DOI) means a two-step signup. Someone enters their email, then receives a confirmation email with a link, and only becomes a real subscriber once they click it. Single opt-in skips the second step. The person is on your list the moment they submit the form.
The difference sounds small. In practice it decides who ends up on your list. With single opt-in you get everyone, including typos, fake addresses, and people who signed up someone else. With double opt-in you get only the addresses that exist and belong to someone who wanted in.
Here is the part most English-language articles get wrong, because they write for a GDPR audience and assume Switzerland works the same way. It does not.
Two Swiss laws matter for email. The first is the UWG, Switzerland’s Unfair Competition Act. Article 3 paragraph 1 letter o says mass advertising email needs prior consent, a real sender, and a working unsubscribe in every message. It does not say the consent has to be a clicked confirmation email. A checked box on a form is consent under the UWG.
The second is the revised Swiss data protection act (revDSG), in force since September 2023. It governs how you store and handle the personal data, and it expects you to be able to show that consent was given. It also does not require double opt-in by name.
🇨🇭 Swiss rule Under the UWG, single opt-in is legal for a Swiss shop mailing Swiss subscribers. You need consent, a real sender and an unsubscribe link. You do not need a confirmation email.
So if the law is the only thing you care about, and you sell only inside Switzerland, you can run single opt-in and stay on the right side of it. I still would not, and the reason is in the last two sections.
Most Swiss shops do not sell only inside Switzerland. The day you take an order from Germany or Austria, and put that person on your list, the GDPR applies to that contact. Now the rules are different.
The GDPR does not use the words double opt-in either. What it requires is that you can prove consent was freely given, specific and informed. That is where the confirmation email earns its place. German courts have treated the double opt-in click as the clean way to prove someone asked to be there. Without it, the burden of proving consent sits on you, and a form submission you cannot tie to a real person is weak proof.
🇩🇪 German rule German case law points to double opt-in as the practical way to prove consent. But the confirmation email itself must contain no advertising. A confirmation email that also promotes a product has been treated as an unsolicited ad in its own right.
That last point catches people. They add double opt-in, then put a 10% welcome code in the confirmation email to soften the extra step. In Germany that turns the compliance step into the exact thing it was meant to protect against. Keep the confirmation email empty of any offer. Put the code in the welcome email that comes after the click.
Put the law aside for a moment. Even if you sell only inside Switzerland and never touch a German address, I would still turn double opt-in on, because of what it does to your inbox placement.
Single opt-in lets three things onto your list that quietly damage it. Typo addresses that hard bounce. Spam-trap addresses that some people paste into forms. And angry signups, where someone enters a rival’s address or a public one as a joke. Every one of those hurts the signals Gmail and Microsoft use to decide whether you reach the inbox.
Since early 2024, the mailbox providers have been much stricter about this. A list that grows through single opt-in tends to carry a higher bounce rate and more spam complaints, and both push more of your mail to the spam folder, including the mail your real subscribers wanted.
Double opt-in is the cheapest filter for all of it. The typo never confirms. The trap rarely clicks. The joke signup does not bother. What lands on your list is a set of addresses that exist and belong to someone who wanted your email. That list reaches the inbox, and it keeps reaching it.
The setup is short. In Brevo, double opt-in is a property of the form and the automation behind it, not a global switch, so you build it once per signup path.
- Form: Turn on double opt-in for the form. Brevo generates the confirmation email and the confirmation page.
- Confirmation email: Strip it to one sentence and one button. No products, no code, no banner. In German-facing lists this is not optional.
- Confirmation page: A short thank-you that sets the expectation for what comes next. This is a good place to say the welcome offer is on its way.
- Welcome email: This is where the discount code or the first real content goes, triggered only after the click. This is the email that does the selling.
- Tag by source: Tag each confirmed contact with where they signed up. A popup, a checkout box and a content download are three different intentions, and they deserve different first emails.
That is the whole setup. It takes an afternoon once, and then every new subscriber runs through it without you.
I am not against single opt-in in every case. There are two where it holds up.
The first is a Switzerland-only list with a strong reason to avoid the extra step, for example a checkout signup where the person has already given you a real, verified address by placing an order. That address is confirmed by the purchase itself.
The second is a back-in-stock or a specific-product notification, where the person asked about one thing and expects one email, not a newsletter. Forcing a confirmation click there adds friction to a request that was already clear.
For everything else, and for any list that touches Germany or Austria, double opt-in is the right default. The law allows single opt-in inside Switzerland, but the inbox does not reward it, and the German border removes the choice.
Not sure whether your list is collecting consent you could prove, or whether your confirmation email is quietly breaking German rules? This is what we do at sakto. We set up double opt-in the right way in Brevo, keep the confirmation step clean, and put the selling where it belongs, so your list grows with addresses that reach the inbox
sakto is a Swiss email marketing agency, Brevo-first, built for e-commerce and B2B senders who want their email to work and stay on the right side of Swiss and German law.