Senior Backend.NET Engineer

Key Responsibilities

• Device Services Architecture: Architect, refactor, and build robust backend system services, background workers, and Windows Services using.NET 8 /.NET Core and C# to manage complex device lifecycles.
• Peripheral & Hardware Integration: Integrate, maintain, and interface with vendor-specific SDKs, native APIs, and drivers for physical hardware components (e.g., credit card processing terminals, thermal printers, scanners, and sensory peripherals).
• Low-Level System Communication: Author low-latency communication layers utilizing serial protocols (RS-232/COM), USB, HID, TCP/IP sockets, and native system APIs (Win32/UWP APIs) to communicate with device firmware.
• Fault Tolerance & Reliability: Engineer fault-tolerant state machines, hardware error handling, fallback logic, and automatic reconnection mechanisms to guarantee maximum operational uptime in production environments.
• System Refactoring & Modernization: Modularize and refactor monolithic device drivers and legacy backend codebases into clean, decoupled, and testable service abstractions.
• PCI & Compliance Standards: Ensure peripheral transactions and peripheral data flows adhere strictly to security standards, PCI compliance, and hardware-level encryption protocols.

Required Qualifications & Technical Skills

• Experience: 5+ years of professional backend software engineering experience with C# and the.NET ecosystem (.NET Core /.NET 8 /.NET Framework).
• Hardware Integration Expertise: Demonstrated experience building software that interfaces with physical hardware devices, external peripherals, or IoT devices via vendor-specific SDKs and APIs.
• Low-Level & System Services: Deep technical background in authoring Windows Services, background workers, multithreaded systems, and asynchronous messaging architectures.
• I/O Protocols: Familiarity with hardware communication protocols and APIs (Serial/COM, USB, HID, TCP/IP, Win32 APIs).
• Code Quality & Testing: Proven track record of writing unit/integration tests for hardware abstraction layers, leveraging dependency injection, and using Git-based CI/CD workflows.

Core Competencies & Cultural Fit

• Self-Motivated Learner: Eager to dive deep into unfamiliar hardware SDKs, vendor documentation, and low-level system protocols to solve complex technical problems.
• Strong Individual Contributor: Able to take ownership of end-to-end device integration pipelines, troubleshoot physical/hardware edge cases, and execute independently with minimal supervision.
• Reliable Team Player: Values transparent communication and collaborates effectively with backend architects, QA teams, and technical operations.
• Remote-Ready Communicator: Clear, prompt, and detailed technical communication across asynchronous tools (Slack, Teams) and task tracking platforms (Jira, Azure DevOps).

Preferred / "Nice-to-Have" Qualifications

• Experience with POS (Point of Sale) systems, payment terminal integration (PCI-DSS compliance, EMV processing), or self-service terminal/kiosk architectures.
• Familiarity with C/C++ interop (P/Invoke) or native C-DLL wrappers within.NET applications.
• Understanding of diagnostic logging, telemetry, and remote hardware monitoring frameworks.
• AI-Assisted Development: Proficiency in utilizing AI-driven tools (e.g., GitHub Copilot, Cursor, Claude Code) to analyze legacy drivers, mock peripheral interfaces for testing, and accelerate development.