What Domain Is .si? Slovenia's TLD, the 2026 'Super Intelligence' Surge, and Who Should Use It

.si is the country code top-level domain for Slovenia. It has been live since 1992, it is run by ARNES (Slovenia's academic and research network) through the Register.si registry, and for most of its life it was a quiet, mostly local extension. Then in September 2026 it became one of the fastest-growing TLDs in the world. This guide covers what .si actually is, the rules for registering one, what it costs, and whether it makes sense for your project.

Which Country Owns .si?

Slovenia, a member of the European Union since 2004 with a population of about two million. The two-letter code comes from the ISO 3166 standard, the same list that gives Germany .de and the United Kingdom .uk. Unlike .io or .ai, there is no sovereignty dispute hanging over .si and no risk of the code being retired. It is an ordinary, stable country code backed by a long-established registry.

Can Anyone Register a .si Domain?

Yes. Registration has been open to the world since 2005, and there is no local presence requirement. Individuals and companies anywhere can register a .si name through an accredited registrar for one to five years at a time. A few rules do apply:

• Names are 2 to 63 characters: letters, digits, and hyphens, with no leading or trailing hyphen
• Contact details must be accurate and current. Slovenia falls under the EU's NIS2 rules, so the registry expects a real name, postal address, email, and phone number
• WHOIS privacy is not offered the way it is on .com. Expect your registrant data to be held by the registry, though public display is limited under GDPR
• Disputes are handled under ARNES's own alternative dispute resolution procedure rather than ICANN's UDRP

How Much Does a .si Domain Cost?

The registry's wholesale price is roughly €10 per year, which keeps retail prices sane. Budget registrars list .si at around $10 to $15 per year, while some brand-protection providers charge $70 or more for the same name with extra handling. On domhaul a standard .si registers for about $14 for the first year, and you see the live price before you pay.

Why Did .si Suddenly Take Off in 2026?

For thirty years .si averaged a couple of thousand new registrations a month, mostly Slovenian businesses. That changed in late September 2026, when 'super intelligence', abbreviated SI, entered the US political vocabulary as a proposed replacement for the term artificial intelligence. Within days, registrations spiked to well over 40,000 in a single month, an increase of more than twenty times, and the zone passed 230,000 names. Dynadot reported that more than half of the .si names registered during the surge were relisted for resale immediately.

The pattern is familiar from .ai, which went from Anguilla's obscure country code to a $100-a-year tech default once the AI boom hit. Whether .si holds its new audience depends on whether the 'super intelligence' label sticks, but the registry and the price are not going anywhere, so there is little downside to holding a good one.

The Other Reason to Want .si: Domain Hacks

Long before the surge, .si was prized for one trick: thousands of English words end in 'si'. Drop the suffix and you get a short, memorable domain hack. Some well-known examples:

• pep.si: Pepsi's short link domain
• jit.si: the Jitsi open-source video conferencing project
• qua.si, fanta.si, odys.si: the kind of invented-word names that read as a single brand

'Si' also means 'yes' in Spanish and Italian, which gives brands in those markets a built-in affirmative. If your brand name or a key word ends in -si, the .si version is often shorter and more distinctive than any available .com.

Does .si Hurt SEO?

Not if you target a global audience the right way. Google treats most country codes as geo-targeting signals, so a .si site is assumed to be for Slovenia unless you tell Search Console otherwise. The fix is to set your international targeting explicitly and use hreflang where relevant. .si is not on Google's list of 'generic' country codes the way .io and .co are, so this step matters more than it does for those extensions.

.si vs .ai vs .io: Which Should You Pick?

• .ai: the recognized AI default, but roughly $90 or more per year and crowded; the obvious names are gone
• .io: the developer classic at about $35 per year, now shadowed by the Chagos Islands handover and its uncertain future
• .si: $10 to $15 per year, stable EU registry, good names still available, and a fresh association with 'super intelligence' if that is your space