The key technology in the functioning of mobile payment apps is near-field communication (NFC). NFC allows devices to communicate wirelessly over short distances, enabling secure transactions by simply tapping or scanning devices together. This technology is widely used in smartphones and contactless payment cards, facilitating quick and convenient payment experiences. It enhances the integration of digital wallets, making transactions seamless and user-friendly. Security features such as encryption are also built into NFC, ensuring that sensitive information is safeguarded during transactions.