Senior Software Engineer – .NET |C# |AWS | E-Commerce

Senior Staff Software Engineer –.NET |C# |AWS

Elan Partners is seeking a Senior Staff Software Engineer with deep .NET/C# expertise to design and help drive the backend architecture of a large-scale, consumer-facing commerce platform processing billions of dollars in annual transactions. This is a highly technical, hands-on engineering role for someone operating between the Senior and Principal level, with near-architect-level system design capabilities. The ideal candidate has experience building high-volume, customer-facing transactional systems from the ground up and understands what it takes to design systems for scale, reliability, performance, and security.

The environment is cloud-native and AWS-based, with a core backend stack  and C#. Experience with e-commerce, payments, PCI-regulated platforms, ordering, fulfillment, or other high-throughput transactional environments is strongly preferred.

• Advanced hands-on development experience  and C#
• Strong system design and distributed systems architecture experience
• Experience designing and scaling microservices-based, cloud-native applications
• Deep experience with AWS, including services such as ECS/EKS, RDS, SQS, and related cloud infrastructure
• Experience building or playing a significant role in building a high-volume, customer-facing transactional platform from the ground up
• Experience designing systems where scalability, availability, latency, data integrity, and fault tolerance are critical
• Experience supporting highly available, production-critical applications
• Strong understanding of observability, monitoring, incident response, and long-term system resilience
• Ability to identify and resolve performance bottlenecks, scaling challenges, and architectural risks
• Strong technical leadership skills with the ability to establish engineering standards and mentor other engineers
• Excellent communication skills

• Experience with in e-commerce, payments, PCI-DSS, ordering, fulfillment, or other high-volume transactional environments
• Experience building multiple large-scale transactional platforms or participating in multiple significant ground-up implementations
• Experience designing systems for PCI-DSS compliance, secure data handling, and fraud-prevention considerations
• Experience establishing backend architecture patterns and engineering best practices across development teams
• Thoughtful, practical use of AI-assisted engineering tools, such as Claude or similar development-focused tools, while maintaining strong engineering fundamentals and technical judgment

• Design and own distributed backend systems  within a cloud-native AWS environment
• Build and scale microservices supporting high-throughput transactional workloads
• Lead system design and architectural decisions impacting performance, scalability, reliability, and security
• Ensure mission-critical services meet demanding requirements for availability, latency, fault tolerance, and data integrity
• Design and maintain secure systems supporting PCI-DSS and transactional processing requirements
• Drive improvements in system observability, monitoring, incident response, and production health
• Identify and resolve system bottlenecks, architectural risks, and scaling challenges
• Define backend engineering standards, architectural patterns, and development best practices
• Partner with product and business stakeholders to translate complex requirements into scalable technical solutions
• Mentor engineers and help elevate technical capability across the engineering organization