The Senior Android Developer (POS) is responsible for designing, developing, and optimizing Android - based Point of Sale (POS) applications, with a strong focus on payment integrations and hardware interaction. The role requires deep expertise in POS ecosystems (Sunmi & PAX), secure payment technologies, and smart card integrations . 1. POS Application Development Design, develop, and maintain Android POS applications for Sunmi and PAX devices. Handle device - specific integrations including printers, card readers, scanners, and peripherals. Optimize application performance for embedded POS environments with limited resources. Ensure compatibility across different POS SDKs and hardware architectures . 2. Payment & Transaction Processing Implement and manage payment flows using EMV (contact & contactless) standards. Integrate transaction messaging using ISO - 8583 protocols. Ensure secure handling of financial transactions in compliance with industry standards. Troubleshoot and resolve...