Ktoto.info is a Polish online service that helps people identify unfamiliar phone numbers before deciding whether to answer. Its reverse phone directory lets users search by number rather than by a person’s or organization’s name, with information drawn from an archive containing thousands of numbers associated with companies and institutions. The service is free to use and says it does not require payments or paid text messages.

A key feature is its community-generated feedback. Users can leave comments describing who called, the purpose of the call, and whether it seemed unwanted or important. They can also rate numbers on a five-point scale ranging from negative and irritating to good and positive. These shared reports help visitors assess potential telemarketing, spam, suspicious calls, or legitimate contacts, while recognizing that experiences and comments come from individual users.

Ktoto.info also publishes a blog with information about phone safety. The site is funded by advertising and says it aims to keep ads minimally intrusive and aligned with Better Ads Standards.