Domain Extensions Guide

A curated, alphabetical list of common top-level domains, last updated June 2, 2026

Most startup founders end up picking from the same dozen domain extensions. Which one you choose tells investors and customers something about your stage, your category, and how seriously you take signaling. This guide gives you the short list to pick from, the full reference table for everything else, and a founder FAQ at the bottom for the questions that come up at pre-seed and Series A.

Looking to check a specific name? ZenTLD is a free macOS menu bar utility that searches domains across the extensions you care about, directly with the authoritative source for each. No middleman.

If you're picking a domain for a startup

The short list, with what each TLD signals and where it lands relative to your stage:

• .com — still the default. If a good .com is available at fair price, take it. Investors expect it. Customers find it. ~$10-15/yr.
• .ai — strong fit for AI/ML startups. Reads as serious. ~$60-90/yr, which is irrelevant once you have revenue, noticeable at pre-seed.
• .io — the de facto tech TLD since the 2010s. Pricing ~$30-50/yr. Has a long-term sovereignty question (see the .io row in the table), real but not yet acute.
• .co — short, brandable, ~$25-35/yr. Used by t.co. Most clean .co names are already taken at this point.
• .app — Google-run, HTTPS-only by design. Reads consumer or mobile-first. ~$14-20/yr.
• .dev — Google-run, HTTPS-only. Reads developer-tool or infra. ~$12-18/yr.
• .xyz — cheap (often $1 first year), broad. Used by Alphabet at abc.xyz. Good when brandability matters more than category signaling.
• .so — short, fewer conflicts than .com or .io. Reads modern.
• .tech — explicit, broad. Reads as B2B tech company.
• .me — personal branding, single-founder portfolios, about-me pages.

Avoid for primary brand if you can:

• Country ccTLDs that require local presence if you might raise or expand internationally (.de, .ca, .au, .no, .jp, .nl all have presence rules of various strictness).
• Heavily sanctioned or geopolitically exposed ccTLDs (.ru and .by carry sanctions risk for many use cases; .ir similar).
• .tk currently has no new free registrations and is in limbo since Freenom shut down its program.
• Restricted TLDs you can't pass verification for (.bank, .gov, .edu, .mil).

The full reference table

Prices are approximate first-year retail at major registrars as of mid-2026. Actual prices vary by registrar (Namecheap, Cloudflare, Porkbun, GoDaddy, etc.) and by promotion. Renewal prices may be higher than first-year, especially on newer gTLDs.

A note on accuracy

Launch dates here are the year the TLD was first delegated by IANA. Some TLDs were dormant for years before they were actively marketed (.co relaunched in 2010, .tk took off in the 2000s, .me opened to global registration in 2008 after a 2007 allocation). Country labels reflect the registry, not necessarily where the TLD is popular today. "Operator" is the registry organization; some TLDs use a separate back-end provider (most ccTLDs).

This list is curated to roughly 86 of the most frequently asked-about TLDs. There are around 1,500 TLDs in IANA's root zone overall, including many brand TLDs (.google, .apple, .audi), category TLDs (.lawyer, .photography), and country codes for territories not listed here. The full root-zone database lives at iana.org/domains/root/db.

Choosing a TLD: principles for founders

• .com is still the default. If a clean .com is available at fair price, take it. Investors expect it, customers find it without typing the extension, and partner channels rarely question it.
• Signaling is real, but secondary to defensibility. A clean .ai is a strong signal at pre-seed. By Series A the company name matters more than the extension. By Series C nobody is asking about your TLD.
• Trademark first, register second. Check USPTO TESS (and the equivalent in your launch markets) before committing. A perfect domain on a conflicted name is worse than a slightly compromised domain on a clean trademark.
• Don't get locked into a country ccTLD if you might exit internationally. Some ccTLDs require ongoing local presence to renew; that becomes a problem the day you incorporate offshore or get acquired by a foreign buyer.
• Repurposed country codes carry policy risk. .io, .ai, .tv, .me, .co, .ly, and similar can in theory be affected if the underlying country's politics change. ICANN has policies that limit registry behavior, but the risk is non-zero. For a multi-year brand bet, hedge with a backup TLD pointing to the same site.
• .app and .dev are HTTPS-only. Both Google-run TLDs are HSTS-preloaded into browsers. Good for trust. A non-starter if your stack temporarily needs plain HTTP.
• First-year promo pricing is a trap. Many new gTLDs are $1-5 for the first year and $30-60 at renewal. Read the renewal terms before buying, especially for .online, .shop, .store, .top, .xyz.
• Restricted TLDs are restricted. .bank, .gov, .edu, .museum, .au, .ca, .no and others require verification or presence. Don't pick them unless you can pass the check.
• Turn on WHOIS privacy. Available at major registrars (Namecheap, Cloudflare, Porkbun, Google's successor in the registrar space). Default on. Keeps personal info out of the public WHOIS record.

Founder FAQ

Is .ai worth $60-90 per year vs $10-15 for .com?

If your product is AI-first and you can't get a good .com, yes. The signaling is real. Series A and later investors notice .ai domains less now than they did in 2023, but customers still do. The cost difference is irrelevant once you have revenue, and is noticeable at pre-seed when every dollar counts.

Should I use .com or .ai for an AI startup?

If both are available, get both. Point one at the other so the brand stays unified. If you can only get one, pick the one with the cleaner name. A clean .ai beats a hyphenated .com.

Is .io safe long-term?

Probably, but it is not zero risk. The British Indian Ocean Territory's sovereignty has been disputed, and the UK has signalled a transfer of Chagos to Mauritius. ICANN's general policy is that ccTLDs survive sovereignty changes, but no one has stress-tested this at the .io scale. For a 10-year brand bet, hedge with a backup TLD. For an MVP, .io is fine.

How much should a seed-stage startup spend on a domain?

Under $100/year on registration fees is normal. Under $5,000 total is the usual ceiling for buying a premium name from a current holder at the seed stage. Spending more than that is a signal you've fallen in love with a specific name, which is rarely worth it before product-market fit.

When should I register multiple TLDs?

Once you have a confirmed company name and either traction or funding. At that point register .com, .ai (if AI-relevant), .io, .co, and obvious typos of your brand. Total cost is around $200/year. Earlier than that and you're hoarding names you may not use.

Should I worry about domain front-running?

Front-running (a domain-check site registering a name you searched and reselling it) has been documented at least once at a major registrar that settled a class action in 2008. The clean defense is not to expose your search through any third-party domain-check site in the first place. ZenTLD queries the authoritative source for each domain directly, with no middleman.

Does the TLD affect SEO?

Modern Google ranks ccTLDs as geographically relevant by default, which can help or hurt depending on your target market. New gTLDs (.app, .dev, .ai, .xyz) are treated like generic TLDs and do not get a geo-boost or geo-penalty. .com is treated as generic globally. There is no documented direct ranking penalty for any newer gTLD as of 2026.

Further reading

• ZenTLD tutorial: every feature of the app explained.
• Security and verification: notarization, SHA-256 verification, and the privacy model.
• IANA root zone database: the official, complete list of every TLD.