Senior Back-end Engineer (.NET Modernization & Architecture)

Experience and Skills

• 8+ years of experience in software engineering, with at least 5 years dedicated to backend development using .NET and C#.
  C1 English level or higher.
  Proven experience leading large-scale migrations from legacy .NET Framework to .NET Core or .NET 8+.
  Strong production experience with Clean Architecture, CQRS, and MediatR.
  Hands-on experience with AWS services, specifically ECS Fargate and RDS.
  Proficiency in MySQL, using both Dapper for high-performance queries and Entity Framework Core for domain modeling.
  Active experience utilizing AI development tools, such as Claude Code or similar, to accelerate development and testing.

  Skills
  .NET
  .NET 8
  Clean Architecture
  CQRS
  MediatR
  AWS
  AWS ECS Fargate
  AWS RDS
  MySQL
  Dapper
  Entity Framework Core
  Claude Code

Key Responsibilities

• Design and lead the backend architecture using .NET 8+ under Clean Architecture and CQRS patterns.
• Define secure API contracts with frontend teams and implement reliable integrations with payment providers.
• Optimize database access using Dapper for critical queries and EF Core for domain logic.
• Make macro-level architectural decisions, evaluating and clearly communicating technical trade-offs to stakeholders.
• Collaborate through close pair programming with backend peers and coordinate regularly with frontend and AI team members.
• Leverage AI tools responsibly to accelerate development cycles while maintaining rigorous human code review and testing standards.
• Proactively identify and communicate timeline or scope risks during daily syncs and adapt plans accordingly.
• Manage deployments and environment-specific pipelines across AWS ECS Fargate and RDS.

Benefits

Work on a business-critical modernization program for a US tax-software company, rebuilding a legacy backend with .NET 8+, Clean Architecture, CQRS, MySQL and AWS. This is a fully remote, full-time contractor role for candidates based in the listed LATAM locations, paid monthly in USD.

You will have meaningful influence over architecture and technical trade-offs, with potential for long-term collaboration.

Nice to Have

• Microservices
• Apache Kafka
• AWS SQS
• AWS SNS
• Model Context Protocol

This senior role centers on leading a high-impact backend migration from legacy .NET systems to a modern .NET 8+ architecture. Working within a dynamic, fast-paced environment, you will collaborate closely with technical leadership to rewrite the backend from scratch, leveraging Clean Architecture, CQRS, and advanced AI-assisted development tools. This position demands a macro-level architectural vision, hands-on AWS deployment experience, and the ability to proactively manage technical trade-offs while collaborating with backend, frontend, and AI specialists.