We offer a reliable, short-range 1:1 ultrasonic communication and authentication SDK that allows for contactless transactions between a client and host device within a distance of one foot. Our SDK includes capabilities for signal generation and decoding, and is compatible with mobile, desktop, and embedded systems. By enhancing the checkout process globally for retailers and transportation enterprises, we provide payment and proximity-based experiences that enrich the retail customer journey. Our solutions also extend to payment and authentication in automotive, transportation, and ticketing sectors. We support device-agnostic transmission and software, granting clients control over the user experience, transport layer, and business model. With the ability to accommodate encryption, cryptography, key exchange, and full duplex, multi-channel features, we facilitate the most secure transmission methods available. By combining our short range with user experience control, we enable quicker and more seamless checkout processes, ultimately elevating customer satisfaction and operational efficiency. Our technology not only streamlines transactions but also enhances the overall engagement between customers and brands.