Compactor is made out of love for domains, especially short ones. It uses multiple techniques to shorten words, names, and brands into domains that can be used for projects, personal sites, short brand URLs, or whatever else you set your mind to.
Yes, it's completely free for you to use. We use affiliate links for domain registrations in order to help keep the lights on.
DNS queries are used to check the availability of domains. Unfortunately, it's possible for registered domains with no nameservers to appear as available, along with domains reserved by the operator. This happens with about 5% of domains suggested.
The domain prices come directly from the registrars so they're mostly accurate. The actual price might be higher or lower depending on the domain. For example, the domain might be premium and priced higher by the registrar or the registrar might apply a coupon resulting in a lower price.
Domain length restrictions are actively tracked and respected so you shouldn't see domain suggestions that can't be registered due to length restrictions. Some domains have extra restrictions that aren't accounted for, like requiring a trademark or local presence. Those restrictions should be presented by the registrar before the registration is processed.
All public TLDs are used for suggestions except ao, bw, cd, cu, gu, ir, kh, km, pg, and sy. Those TLDs either have special restrictions or aren't offered by the registrars recommended by Compactor.
Multiple registrars are recommended in order to cover as many TLDs as possible. The ordered list is: Dynadot, Namecheap, 101Domain, and Nominus. Most domains will fall under Dynadot and 101Domain, who specializes in ccTLDs. All registrars are ICANN-accredited.