Take part in the full development lifecycle of our card platform
Work on mission-critical services used in card application flows for Debit, Credit, Prepaid, Digital & Commercial cards
Integrate with KKB/LKS, Decision Support, Analytics Solutions and onboarding systems
Develop card lifecycle and transaction management services (issuance, renewal, limits, fraud, posting, fee, campaign, extre, DWH etc.)
Implement secure integrations with payment schemes (Visa, Mastercard, BKM, CUP, Discover) and EMV scripting/PIN management
Manage POS ecosystem integrations (TechPOS, Ingenico SDK, CAT transaction flows, parameter distributions)
Ensure real-time and batch transaction processing with high availability (99.9% uptime) requirements
Work with ISO 8583 messaging, socket programming, TCP/IP protocols
Support authentication flows via OAuth2, OpenID Connect, JWT/JWS, and 3DS SDK/ACS

Minimum 5+ years of experience in software development
Bachelor’s degree in Computer Engineering, Software Engineering, or related field
Strong experience in C#, .NET Core / .NET Framework
Solid command of SQL / PL-SQL (Oracle preferred)
Experience in multi-threaded applications and performance optimization
Prior banking or fintech experience is highly preferred
Hands-on with RESTful API, Webhook integrations
Strong debugging, testing, and system integration skills
Good command of English is a plus

Senior Backend Developer – Card Payment Systems

Key skills