What is a .io domain? And is it still a good choice in 2026?

The basics

.io was assigned to the British Indian Ocean Territory (BIOT) by IANA in 1997. The territory consists of the Chagos Archipelago, a group of uninhabited atolls in the central Indian Ocean. Diego Garcia, the largest atoll, hosts a US-UK military base; the original Chagossian population was forcibly removed in the 1960s-70s and has been fighting in international courts for their right of return ever since.

The .io registry is operated by Internet Computer Bureau Ltd (a private company) under contract from the UK government. Global registration has been open since the start; technically anyone can register a .io for any purpose.

How .io became a developer/startup TLD

Two things drove .io's rise around 2010:

• The string "io" reads as "input/output" — a fundamental computer-science concept. Developers latched onto this immediately.
• The matching .com for many short tech names was already gone. .io offered a cheap (though pricier than .com) way to get a 4-5 letter name.

By 2015, .io was the obvious second choice for any tech startup. By 2020, it had passed .net in technical-audience preference. Famous examples: github.io (GitHub Pages hosting domain), npm.io, replicate.io, fly.io, observable.io, vercel.io (now vercel.com).

The 2024 sovereignty wrinkle

In October 2024, the UK government announced it would transfer sovereignty over the Chagos Archipelago to Mauritius. The deal involves a 99-year UK lease back on Diego Garcia for the military base. The treaty is expected to be ratified through 2025-2026.

What this means for the .io TLD is officially "no immediate change." IANA has not announced a transfer or sunset of the .io ccTLD. Existing registrations renew normally. But the historical precedent for ccTLD migrations (when a country/territory disappears or changes status) involves either an immediate sunset, a multi-year migration window, or — most commonly — a quiet transfer to the new sovereign's management.

Pricing and registration

When .io still makes sense

• Your product is developer-facing and the technical audience expects .io.
• You're building a project that will be replaced or rebranded within 3-5 years anyway (e.g., a launch-stage MVP).
• You can't get the .com and don't want .ai's "AI-only" connotation.

When to skip .io now

• You're building for a 10+ year horizon and the BIOT/Mauritius transition worries you.
• .dev is available and your product is developer-focused — .dev is now arguably the cleaner choice (always-HTTPS, no geopolitical risk, lower cost).
• Your audience is not technical — most consumers still hear ".eye-oh" as a new TLD they don't fully trust.

Famous .io brands

• github.io — GitHub Pages
• fly.io — application platform
• replicate.io — ML model hosting
• tldraw.io — collaborative whiteboard
• observable.io — JavaScript notebooks