4Bell Technology

Job Description

Key Responsibilities

• Design, develop, test, and maintain Android applications for payment and POS solutions.
• Develop Android applications and SDK integrations for PAX payment terminals/devices.
• Integrate payment applications with payment gateways, processors, acquirers, and backend services.
• Implement and maintain payment transaction flows such as:
• Sale / Purchase
• Refund
• Void
• Reversal
• Pre-authorization / Completion
• Settlement
• Tips and other payment-related flows as applicable
• Work with PAX device APIs/SDKs for peripherals such as:
• Card readers
• PIN pads
• Printers
• Barcode/QR scanners
• NFC/contactless interfaces
• Integrate and troubleshoot EMV, NFC/contactless, chip-and-pin, and magnetic-stripe payment flows.
• Handle device communication and integration with payment peripherals and external services.
• Implement secure handling of sensitive payment and transaction data.
• Diagnose and resolve production issues involving payment transactions, device connectivity, and terminal behavior.
• Collaborate with backend engineers to integrate REST APIs and payment services.
• Write clean, maintainable, and testable Kotlin/Java code.
• Participate in code reviews, technical design discussions, and architecture decisions.
• Work closely with QA teams to define test scenarios covering payment and device-specific use cases.
• Support certification, integration testing, and deployment of payment applications on PAX terminals.
• Investigate transaction logs and device logs to identify and resolve payment-related issues.