Domain extensions: .com vs .ai vs .io vs .co and more
A domain extension, or top-level domain (TLD), is the part after the final dot, like .com. It shapes trust, memory, price, and positioning. The right TLD depends on your audience, category, budget, and whether the name needs to work globally or within a specific tech community.
Domain extension comparison
| Extension | Best for | Watch out for |
|---|---|---|
| .com | General businesses, consumer brands, global audiences. | Good short names are often taken or expensive. |
| .ai | AI products, machine learning companies, research labs. | Renewals run higher than .com. Less recognized outside tech. |
| .io | Software tools, SaaS products, developer-facing brands. | Audience fit is strong in tech but weaker outside it. |
| .co | Startups wanting a short .com alternative. | Some users still type .com out of habit. |
| .app | Mobile apps, web apps. Requires HTTPS by default. | Narrower brand fit — works when "app" is central to identity. |
| .dev | Developer tools, libraries, open source projects. | Very specific audience — not suited to general consumer brands. |
| .net | Network products, infrastructure, technical services. | Feels dated for new consumer-facing brands. |
| .org | Nonprofits, communities, open source foundations. | Can feel mismatched for commercial products. |
The practical rule for choosing an extension
If you can get a short, clean .com at a sensible renewal price, it is still the safest default for most brands. When a user hears your brand name out loud, .com is the extension they are most likely to type first.
If the right .com is genuinely unavailable or expensive, a strong alternate extension can win. A short, memorable name on .ai or .io beats a long, awkward .com that nobody can remember. The extension matters less than the name itself when the name is strong enough.
Does the extension affect SEO?
Google's guidance says keywords in a TLD give no ranking advantage or disadvantage, and that it handles new generic TLDs like .app and .dev much as it handles .com. Country-code TLDs can signal a country, though Google treats some, such as .io and .ai, as generic. Your content matters far more than the extension.
Extension prices vary significantly
The renewal price gap between extensions is often larger than people expect. On October 31, 2026, our live check across Porkbun, NameSilo, and Cloudflare Registrar found renewals of $10.46 to $17.29 for .com, $50.00 to $69.99 for .io, and $80.00 to $99.99 for .ai, before taxes and fees. See the full dated table, and check renewal cost alongside registration cost before choosing any extension.
Opens TLDs mode with the same name across .com, .ai, .io, .co, .app, and more. The first 8 show live prices, and Check more prices the rest.
A real example
We compared northwind across all 14 extensions in TLDs mode. None came back verified available. When a common word is gone everywhere, changing the word usually works better than trying a less familiar extension.
From one search on October 31, 2026. Prices exclude taxes and fees, and results change.
Frequently asked questions
- Is .com still the best domain extension?
- In our judgment, .com remains the safest default for broad audiences, because it is the extension most people type first. For tech-focused products, .io and .ai are well-established alternatives.
- Is .ai a good extension?
- .ai carries strong category recognition for AI products, labs, and data companies. The main tradeoffs are higher renewal costs ($80.00 to $99.99 per year vs $10.46 to $17.29 for .com in our October 31, 2026 check) and weaker recognition outside the tech industry.
- What is the difference between .io and .co?
- .io is associated with software tools, SaaS, and developer products. .co is used as a short company or startup alternative to .com. Both are recognized in tech communities. In our October 31, 2026 check, .io renewed at $50.00 to $69.99 and .co at $30.00 to $38.99.
- Do .app and .dev require HTTPS?
- Yes. Both .app and .dev are on the HSTS preload list, which means browsers enforce HTTPS connections by default. This is a security feature and a non-issue for any modern web product.
- Does the TLD affect SEO rankings?
- Not directly. Google says keywords in a TLD give no ranking advantage, and country-code TLDs are the main exception because they can signal a country. Your content and links matter far more than your extension choice.