When you find a name you like, the next question is which extension to register. The honest answer is that .com still wins by default, and the alternatives are good when the .com is gone. Here is how they actually compare.
.com: the default
The .com is what people type without thinking and trust without checking. That habit is decades deep and not going away. If your name has its .com free, take it. It is the lowest-friction choice and the one least likely to send a customer to the wrong place.
The only real downsides are price and scarcity: good .com names go fast, and some are flagged premium and priced high.
.io: the tech favourite
The .io extension reads as normal to developer and startup audiences, which is why so many tools use it. It often has a short name free when the .com is long gone. For a product aimed at a technical crowd, .io is a perfectly respectable home.
The caveat is the wider public, who still default to .com. If you expect non-technical customers, make sure the .com is not owned by a competitor.
.co: the short global alternative
The .co extension is a clean, short stand-in for .com that works across industries. It is easy to say and increasingly familiar. It is a strong choice when your .com is taken and you want something that still feels general-purpose rather than niche.
.ai: for anything AI-flavoured
The .ai extension has become the obvious pick for AI products, and many strong names are still free on it. It tends to cost more than the others, so factor that in. Outside AI it can read as off-topic, so it suits the category more than general brands.
.dev, .app and friends
These do specific jobs well. The .dev and .app extensions enforce HTTPS, which is a small plus, and they signal exactly what they are. They are great for developer tools and apps and less suited to a general brand.
How to choose when the .com is taken
- Check whether the .com is owned by a competitor or something harmful. If so, the name is risky regardless of which extension you buy.
- Match the extension to your audience: .io or .dev for technical, .co for general, .ai for AI.
- Pick the shortest, cleanest option that is free.
- If you can, also register the .com later to protect the brand.
The domain name generator on this site checks all of these extensions at once for every name idea, so you can see which is free and pick on evidence instead of habit. Find a name where your preferred extension is open, and register it before it is gone.