For most teams, the best domain for an AI startup is the exact-match .com or .ai. A .si domain makes sense in narrower cases: when the SuperIntelligence reading is part of the brand, for a single product or campaign, or as a defensive, Slovenian or EU address. Google reads .si as a Slovenia signal, so plan around it.
Interest in .si jumped in September 2026. Register.si recorded 46,066 new .si registrations that month, against 3,515 in August, after “Super Intelligence” entered US political language. Search data still lags. On October 5, 2026, Ahrefs showed about 30 US monthly searches for “best domain for ai startup” and 700 US (3,300 global) for “.si domain”. Both are 12-month averages, so the September spike does not show in them yet.
This guide compares .com, .ai and .si on the points that decide the choice: Google treatment, cost, eligibility, risk and fit. It relies on primary sources and our own audit, all checked on October 5, 2026.
What a .si domain signals
A .si domain signals Slovenia to search engines and, to an AI audience, a possible SuperIntelligence reading. The first is a technical fact; the second is a branding choice.
.si is Slovenia’s country-code domain. For AI companies it reads as SuperIntelligence. That reading is our framing, not an official meaning. Executive Order 14434 of September 29, 2026 made “Super Intelligence” the term for AI in US federal executive-branch communications, but it has nothing to do with the .si domain.
Legally, .si is a ccTLD run by Register.si, the registry operated by ARNES. Under the Register.si general terms, the holder can be a legal or natural person, and the terms set no residency rule. Names can be 2 to 63 characters long, IDN characters are supported, and a registration runs for 1 to 5 years.
Registration works only through accredited registrars, because the registry does not sell names directly. Register.si listed 94 registrars on its homepage on October 5, 2026. Our complete guide to the .si domain covers the rules in more depth.
What the data shows about .si and AI companies
So far, AI companies use .si names as redirects and brand protection, not as primary sites. Registrations surged in September 2026, but live AI products on .si remain rare outside Slovenia.
In our audit of the Forbes 2026 AI 50, checked on October 5, 2026, none of the 50 companies runs its main website on .si. The split is 48% on .com and 38% on .ai. We also requested the exact brand.si name for all 50 companies: only replit.si redirected to its company, while 29 showed for-sale pages.
The visible .si uses by AI firms are pointers. On October 5, 2026, recursive.si redirected to recursive.com, the site of the superintelligence lab Recursive, and copilot.si redirected to Microsoft’s Copilot page. In both cases the .si name works as a backup address, not as the product home.
The clearest live AI service on .si is Slovenian. The povejmo.si platform hosts GaMS, a chatbot built on a Slovenian-language model from the University of Ljubljana. Domain Name Wire found the same gap on October 1, 2026. A ProductHunt tracker showed no startups launching on .si in the previous 30 days, while 50 launches that day used .ai.
Registrations tell a different story. Register.si counted more than 300,000 .si domains on October 5, 2026, after 46,066 new names in September. Netcraft reported on September 24, 2026 that about 52% of the .si names it saw registered at one large registrar early in the rush were listed for resale.
.com vs .ai vs .si: how the three compare
At registry level, .com costs $10.26 per year until November 1, 2026, .ai costs $160 per 2-year registration and .si costs €10 per year excluding VAT. Only .si carries a Slovenia signal in Google. The fee row in the table shows registry prices, not retail prices.
| Factor | .com | .ai | .si |
|---|---|---|---|
| Google treatment | Generic TLD | Treated as generic (on Google’s ccTLD list) | Not on the list: Slovenia signal |
| Registry or wholesale fee | $10.26 per year; $10.97 from November 1, 2026 | $160 per 2-year registration since March 5, 2026 (was $140) | €10 per year excl. VAT, same for every registrar |
| Minimum term | 1 year | 2 years | 1 year (1 to 5 years allowed) |
| Who can register | Open to anyone | Open to anyone; no residency rule | Any legal or natural person; no residency rule in the terms |
| Brand reading | The default, no category signal | AI, the category | SuperIntelligence (our framing) |
| Abuse ranking (Spamhaus, October 5, 2026) | 101st of 193 gTLDs (separate list) | 65th of 103 ccTLDs | 95th of 103 ccTLDs |
The .com figures come from Verisign’s Form 10-Q for the second quarter of 2026. The .ai fee comes from Domain Name Wire’s report on the registry’s price increase, and the .si fee from Register.si. Registrars add their own margins, so retail and renewal prices are higher for all three. Our .ai domain guide covers .ai rules and price history.
The Spamhaus ccTLD reputation ranking lists the worst TLD first, so a higher rank number means a lower bad reputation score. Spamhaus calculates that score from the share of malicious domains among those it observed over the past four weeks. It ranks .com on a separate gTLD list. The ranking measures abuse, not email deliverability. We found no authoritative source linking a TLD to deliverability, so this guide makes no claim either way.
SEO: what Google says about .si
Google treats .si as a country-code domain for Slovenia, while it treats .ai and .io as generic. A .si site can still rank abroad, but it starts with a country signal that a .com or .ai site does not carry.
Google’s guide to multi-regional sites, last updated December 10, 2025, lists ccTLDs it treats like gTLDs, because users and site owners see them as more generic than country-targeted. The list includes .ai and .io, but not .si. For other ccTLDs, Google describes the domain as a strong signal that a site is meant for one country.
You cannot switch that signal off in Search Console. Google says country targeting through Search Console is “no longer supported”, although it still uses hreflang. The extension adds no ranking value of its own either. In its 2015 post on new top-level domains, Google wrote: “Keywords in a TLD do not give any advantage or disadvantage in search.”
For a .si site with a global audience, the remedies are standard: hreflang annotations for each language or region, content written for each market, and links from sites in those markets. Server location is not a definitive signal, according to the same Google guide. Our guide to ccTLDs explains the three common setups for a .si name.
Costs and risks of a .si domain
A .si domain costs €10 per year excluding VAT at registry level, but the larger costs are registrar renewal margins, ARDS disputes (€700 including VAT) and a speculative aftermarket. Check all three before you build on a .si name.
The registry fee is the same for registration and renewal, and the final price depends on the registrar. Over six years, .si registry fees add up to €60, against $480 in .ai wholesale fees for three 2-year terms, before registrar margins. Ask your registrar for the renewal price, not only the first-year offer.
Trademark exposure works both ways. Under Register.si’s ARDS dispute procedure, a rights holder can claim a .si name that is identical or confusingly similar to its own right. That right must hold in Slovenia: a trademark valid there, a Slovenian company name or another right recognized in Slovenia. The claim also requires that the domain holder has no legitimate interest in the name and that the name was registered or used in bad faith.
An ARDS complaint before a single panelist costs €700 including VAT for 1 to 5 domains, or €573.77 for complainants based outside Slovenia. Run a trademark search before you choose a name, and consult a trademark attorney.
In a September 24, 2026 notice, Register.si advised holders of trademarks and company names without a .si domain to register one as soon as possible. The same notice said that media talk of Slovenia earning millions from the rush has no real basis. Both points are our translation from Slovenian.
Typosquatting is a separate risk. Netcraft’s September 24, 2026 report counted more than 44,000 .si names matching an existing .ai name, 22% of all .si domains at the time. Netcraft warned that a .si address is a “one-keystroke typo” of its .ai equivalent, which makes lookalike registrations easy.
Asking prices in the .si aftermarket are offers, not sales. Our guide to domain value explains how to tell the two apart. No extension guarantees that a name will gain value.
Scenarios: when .si fits an AI startup
A .si domain fits when the name itself carries the brand idea or when Slovenia is a real market. It is a weak fit as the only domain of a global, search-led product.
| Scenario | .si fits? | Why |
|---|---|---|
| SI-branded product | Yes | The extension completes the name; plan hreflang, content and links for reach outside Slovenia |
| Campaign or microsite | Yes | Short, time-boxed and cheap at registry level; the country signal matters less for a launch page |
| Defensive registration next to .com or .ai | Yes | Blocks one-keystroke lookalikes of a .ai brand; redirect it to the main site |
| Slovenian presence | Yes | The Slovenia signal helps local search, and any person or company can register |
| Wider EU audience | Partly | .si signals Slovenia only; other EU markets need hreflang or their own domains |
| Global SEO-first product on .si alone | Weak | It starts with a Slovenia signal, and Search Console can no longer override it |
For an SI-branded product, a short and readable name does most of the work. Disclosure: buysidomains.si sells .si names. One example from our portfolio is rapid.si, a word recognized in many languages, at a fixed asking price of €12,000 (October 2026). Our overview of superintelligence domains covers other naming patterns.
A checklist for choosing the best domain for an AI startup
Start with your market and your main domain, then decide what .si adds. Work through these steps in order.
- Decide where your main audience is. For a global product, put the main site on .com or .ai; for a Slovenian product, .si can carry it.
- Check the exact-match .com and .ai first, including the 2-year minimum term and renewal price for .ai.
- Run a trademark search for the name in every market you plan to sell in, and consult a trademark attorney.
- If you hold a .ai brand, register the matching .si to block one-keystroke typos, and redirect it to your main site.
- If .si is part of the brand, plan hreflang, market-specific content and links before launch.
- Ask your registrar for the .si renewal price, and choose a term between 1 and 5 years.
- Treat aftermarket asking prices as offers, and compare them with recorded sales before you pay.
For a global AI product, the decision is mostly settled: buy the best .com or .ai you can, and add .si as a pointer or a deliberate brand play. For a Slovenian team, or a product built around the SI idea, .si can host the main site, provided you accept the country signal and plan your SEO around it.
