What kind can a fi-domain be?

The length of the domain can be 2-63 characters.

Allowed characters are letters a to ö, numbers 0 to 9, and a hyphen (-), as well as characters of the Sámi language spoken in Finland.

The hyphen must not be the first or last character of the domain.
The third and fourth characters must not both be hyphens.
The domain name must not be based on another protected name or trademark. The registers can be checked here.

NOTE! Some e-mail programs do not recognize vocal domains. For example, domain jalöö.fi would be internationally in the form xn--4caa8c.fi.
For e-mail addresses, we also recommend registering a domain with no e-mails (for example, replacing a and o).
Browsers in the browser should appear in their correct form.
For example, the international form of the subdomain domain can be checked here.