Question: I'm looking for a contactless payment system that uses biometric authentication for secure transactions.

If you're looking for a contactless payment system that uses biometric authentication, PopID is a good choice. It uses facial recognition for identity verification and secure transactions, and it can work with different retail models, including cashier/counter service, drive-thru, kiosk and table service. PopID lets you enroll quickly, stores a secure digital key in the cloud, and handles contactless transactions for safety and lower payment processing fees.

Another contender is Callsign. It's a platform that marries behavioral biometrics and machine learning to safeguard digital identities and thwart fraud. It includes an Intelligence Engine for authenticating users and detecting fraud, an Orchestration Layer to manage interactions, and a sophisticated Authentication Suite. Callsign is geared for industries like finance, digital commerce and workforce management, so it's a good choice for companies that want to use it for secure payment transactions.

If you need a cloud-based facial recognition API, Luxand offers a variety of features, including face recognition, liveness detection and emotion detection. It's designed for web and mobile apps and offers custom solutions for biometric authentication, attendance systems and fraud detection. Luxand's cloud infrastructure is designed to scale, and it offers several integration options, so it's a good choice for high-volume photo processing.

Last, nudata Security uses behavioral biometrics, device information and a proprietary trust network to assess and differentiate legitimate users from threats in real time. The system is designed to provide a frictionless user experience while maintaining high security, so it's a good fit for financial services, fintech companies and eCommerce sites that need to balance security and user experience.