.io domains: the most expensive of the popular extensions

Price is the first argument against

At a Polish registrar .io costs 460 PLN net a year, for registration and renewal alike, with transfers at 526,80 PLN (August 2026).

That is six times a .pl name and seven times a .com. Five years on one .io address comes to 2300 PLN net — for a side project, often more than every other cost combined.

Where the popularity came from

Short, easy to say, and free at a time when the .com equivalent had been taken for years. Startups adopted it widely enough that within the industry nobody asks where the territory actually is.

The risk worth understanding

The extension belongs to a dependent territory, and the status of such territories is decided politically. A change of operator, pricing or policy requires nobody’s agreement beyond the registry. The shared ICANN rules that protect .com holders do not apply here.

On top of that, .io publishes no RDAP, so an availability result is an inference rather than a fact.

When it is still worth it

When you are addressing a technical audience, the name is short, and you knowingly treat the fee as a marketing cost. In that case .io does exactly what is asked of it.

When you simply need an address for a company serving one country, the same name in that country extension will cost a fraction as much, check more reliably and read as more trustworthy to customers.