Who runs .one, and why that is unusual
Most new gTLDs are run by registry specialists who never sell to end users. .one is different: the operator, One.com A/S, is a Copenhagen hosting company, and the extension was delegated to it at the end of 2014 and opened to general registration in 2015. Technical operations sit with GoDaddy Registry, so the plumbing is the same industrial infrastructure that runs a large share of the namespace, while the policy sits with a European operator under an ICANN registry agreement.
For a buyer, the practical consequence is that .one is a normal, boring, fully unrestricted gTLD — which for a short extension is a genuine feature. There is no community definition to argue with, no nexus statement, no document to upload and no post-registration audit. If the name is free and it is not on the reserved list, it is yours as soon as the order clears.
The premium tier is the only thing to watch
The one place a .one purchase can surprise you is pricing tiers, and it is worth understanding before you fall in love with a name. The registry withholds single-character labels entirely, prices two-character labels as premium, and puts a list of short dictionary words, numbers and well-known terms into the same premium bracket. That is ordinary practice among new gTLDs, but the important detail is that the premium level attaches to the name permanently.
A premium name does not revert to the standard price at renewal. It renews at its premium level for as long as you hold it, which turns a one-off decision into a recurring cost. This is exactly why registration and renewal are both shown live above from the same pricing engine that will charge your cart: the renewal figure is the one that decides whether a premium .one is a sensible purchase, and you should see it before you buy, not a year later.