.io domain names
Technical credibility, widely adopted by developer-facing products.
Quick answer
.io is the country-code extension for the British Indian Ocean Territory, adopted broadly by developer tools, APIs and technical startups because it reads as "input/output". It signals a technical audience clearly, at a registry price below .ai but above generic extensions.
Check a .io nameWhat .io actually signals
- A country-code extension used almost entirely outside its territory, with no local presence requirement for registrants.
- The "input/output" reading gave it early traction with developer tooling, and that association is now well established.
- Because it is a ccTLD, its long-term administration follows territorial arrangements rather than generic-TLD policy — a consideration for very long-horizon brand decisions.
Registration requirements for .io
Read from the registry data behind our own registration flow, so these are the rules your registration will actually be checked against — not a general description of the extension.
| Requirement | .io |
|---|---|
| Registration term | 1 to 10 years |
| Organization details | Not required — individuals can register |
| Registrant country | No country restriction |
| Nameservers | Optional at registration (up to 13) |
| Internationalised names (IDN) | Supported |
| Transfers | Require an authorization code from the losing registrar |
Registry data last synchronised 2026-08-17 · source: Donuts
Who .io suits
A good fit for
- Developer tools, APIs and infrastructure products
- Open-source projects and technical documentation sites
- B2B software addressing engineers as the primary buyer
.io domains on the marketplace now
Premium .io names currently listed on Name.ai. Availability changes constantly; this list refreshes hourly.
Frequently asked questions about .io
It is a strong fit when the buyer is technical — developer tools, APIs and infrastructure products use it heavily enough that it reads as native. It is a weaker fit for consumer brands, where .com recall still dominates.
Google treats .io as a generic top-level domain rather than geo-targeting it to the British Indian Ocean Territory, so using it does not restrict your search visibility to a region.