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.si Domain Checker: Super Intelligence Domains

.si is the new super intelligence domain, and people are racing to claim names. Check .si domain availability right now, alongside .ai, .com and .io.

How to check if a .si domain is available

Type the name you want into the box above, without the .si, and press Check. This .si domain lookup asks the official Slovenian registry in real time and tells you straight away whether the .si domain is available or already registered, followed by the same name on .ai, .com, .io, .app and .dev. Taken .si domains show their registry status where it's public, which helps you tell a name that's in use from one that might lapse. Because the super intelligence rush is still under way, treat an available result as urgent: a .si name that's free today may not be free tomorrow.

What .si means: the Slovenia domain and super intelligence

Every two-letter domain is a country code, and .si was assigned to Slovenia in 1992. It's run by the Slovenian registry (Register.si) and has always been popular with Slovenian businesses. What changed in 2026 is the meaning of the letters. As "super intelligence" and "SI" entered everyday tech and political language, .si became the obvious home for anything pitched as beyond AI, in the same way .ai (Anguilla) and .io (British Indian Ocean Territory) were adopted by tech for what their letters spell rather than where they come from. Our .si domain guide covers the full story.

.si vs .ai: which should an AI company choose?

.ai is established: users, investors and journalists recognise it instantly, and it's the safe choice for an AI product today. .si is the early bet: it's newer, cheaper to register, and short names are still far easier to find than on .ai. Many teams are doing both, launching on the .ai or .com and holding the matching .si (or the other way round) so their brand is covered whichever term wins. Compare them with the .ai domain checker and the .com domain checker. One real difference for SEO: Google treats .ai as a generic domain, but at the time of writing .si is still treated as a Slovenian country domain, so a .si site may need extra signals (content, links, hreflang) to rank well outside Slovenia.

How to buy a .si domain

Once the checker shows your .si is free, press Register to go to Namecheap with the name filled in. .si domain registration is open through international registrars, typically for one to several years at a time, and the .si domain price is far lower than a .ai: closer to a regular .com. Check the first-year and renewal price at checkout, and check the registrar's current registration requirements for .si before you pay, since country-code registries set their own rules. Turn on auto-renew straight away; with this much interest in .si, a name that lapses is likely to be snapped up.

What to do if your .si name is taken

Many of the obvious single words went in the first weeks of the rush. Try a small, natural variation: add get, try, use, labs or hq (getnova.si, novalabs.si), or pair your word with what it does. Check whether the .ai or .com of the same name is free instead, since the checker shows them together. If a taken .si looks parked or unused, the domain expiration checker shows its expiry date and status, and with Pro, Handle Watch can email you if it starts moving towards deletion. Then run the name through the brand name checker so your social handles match.

Why everyone wants a .si super intelligence domain

.si is the country-code domain of Slovenia, but since September 2026 "SI" has become the official US shorthand for super intelligence (what SI means). That turned a quiet European extension into one of the fastest-growing domains on the internet: new .si registrations reportedly jumped from a few thousand a month to tens of thousands almost overnight. Short, meaningful .si domain names are being claimed every day, so check yours now and register it before someone else does.

A .si domain does for super intelligence what .ai did for artificial intelligence: it tells people what your product is about from the address alone. Founders building agents, reasoning models, research labs and AI-native tools are registering their brand on .si next to the .ai, either to launch on it or simply to stop anyone else taking it while the trend is young. Even the biggest names are affected: see who owns spacex.si after the SpaceXSI rebrand.

This .si domain checker gives you a straight answer in seconds. Type a name and you'll see .si domain availability first, with the same name checked on .ai, .com, .io, .app and .dev underneath, so you can lock in a matching set. If the .si is free, the Register button takes you straight to checkout. Need more extensions? The TLD checker covers 150+, including .si.

.si Domain Checker: Super Intelligence Domains FAQ

Quick answers to the most common questions.

.si is the country-code domain for Slovenia. Since 2026 it has also become known as the super intelligence domain, so AI companies and founders are registering .si names for their brands. Our .si domain guide explains the whole story.

Because "SI" is the abbreviation for super intelligence, which the US government adopted in place of "AI" in September 2026 (SI vs AI explained). The letters, not the country, are what made it popular with tech companies.

Type your name in the box above. The .si result appears first with a Register button if it's free, and the same name is checked on .ai, .com, .io, .app and .dev. To check a list of names, use the bulk domain search.

.si names are sold by international registrars such as Namecheap. Country-code registries set their own rules, so check the current registration requirements at checkout before you buy.

A standard .si costs far less than a .ai, usually closer to the price of a .com. Prices vary by registrar, so compare the first-year and renewal price at checkout.

.ai is more established and recognised today; .si is newer, cheaper and has more short names left. If your brand is built on AI, owning both is the safest option: check the pair with the .ai domain checker.

It doesn't hurt, but at the time of writing Google treats .si as a Slovenian country domain rather than a generic one like .ai, so a .si site aimed at a global audience may need more content and links to rank outside Slovenia.

spacex.si has been registered since 2021 and its owner isn't public; x.si isn't registered, and single-letter .si names appear to be unavailable. Details in will SpaceX buy spacex.si?

Short invented words and names that read well with the extension (name.si reads as "name SI"). See 120 super intelligence company name ideas for inspiration.

Try a short prefix or suffix (get, try, labs, hq), or register the matching .ai or .com. If the taken .si looks unused, check its expiry date with the domain expiration checker.

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