Senior Software Engineer (Card Present)
Century Business Solutions4 months ago
Irvine, CA, USASenior
Responsibilities
- Design, develop, and maintain backend services managing communication between payment terminals and processing infrastructure.
- Integrate Clover, Stripe Terminal, Square, and similar card-present providers and adapt their APIs to the platform architecture.
- Build device hub capabilities for terminal provisioning, configuration management, firmware coordination, and health monitoring.
- Own EMV Level 3 certification efforts, including test planning, certification tooling, and resolution of findings.
- Design card-present infrastructure for international markets, regional EMV differences, multi-currency support, and varying acquiring-market certification requirements.
- Build scalable backend services using .NET and C# and contribute to architectural evolution.
- Implement retry logic, timeout handling, and graceful degradation for network instability and device failures.
- Write secure code meeting PCI DSS requirements, including cardholder data handling, encryption, and key management.
- Apply P2PE and tokenization standards within device integration and transaction-processing layers.
- Mentor junior and mid-level engineers through pair programming, code reviews, and knowledge sharing.
- Document card-present domain knowledge, certification processes, integration quirks, and device-specific behaviors.
Requirements
- Strong proficiency in C# and the .NET ecosystem, with experience building production-grade backend services and APIs.
- Hands-on experience with EMV chip, contactless/NFC, and magnetic-stripe payment flows, ideally including EMV Level 3 certification.
- Experience integrating payment terminal hardware and device-management platforms, including terminal communication protocols such as TLV or ISO 8583.
- Understanding of PCI DSS requirements for card-present environments, including encryption, key injection, and secure cardholder-data handling.
- Experience designing and building reliable, clearly versioned RESTful APIs.
- Experience building low-latency, high-reliability backend services in payments or a similarly demanding production environment.
- Direct experience with Clover, Stripe Terminal, Square, or similar card-present platforms and developer SDKs.
- Familiarity with EMV kernel development or customization, regional EMV certification requirements, and acquiring-bank differences across international markets.
- Experience with Ingenico, Verifone, PAX, or other payment-terminal hardware vendors.
- Experience with network tokenization or scheme-token management in a card-present context.
Benefits
- Full-time employment.
- The company describes learning opportunities, career growth potential, and a dynamic work environment.
Tech Stack
C#.NET
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