Doluna is a user verification service that uses a mobile phone for performing two-factor authentication. Once the user submits the recipient's phone number, Doluna generates and sends a one-time PIN code via SMS. At the same time, Doluna gives the user a transaction key which they can check against the recipient's PIN. Doluna can be used to validate end users, verify phone numbers, and protect against fraudulent activity. Integration is accomplished via API and requires simple REST calls.