Senior Backend Engineer (.NET)

About the role

Software Mind is a software engineering partner that builds and scales digital products for companies in the US and Europe, with LATAM teams working directly with client engineering teams. This Senior Backend Engineer position is based in San José and focuses on building the backend of a white-label B2B e-commerce platform for a US promotional products company, which powers multiple branded Shopify Plus storefronts.

Key responsibilities

• Design and build scalable RESTful microservices with ASP.NET Core Web API (.NET 8) and CQRS
• Own core services: Order Management, Inventory, Pricing Engine, Catalog Sync, and Notifications
• Integrate with external systems such as Amazon SP-API, Walmart Marketplace API, ERPs, payment gateways and tax services
• Work with legacy services where the migration is phased or partial
• Write unit, integration and BDD tests (xUnit, Reqnroll, FluentAssertions)
• Define API contracts and inter-service communication (SQS, EventBridge) with the Team Lead
• Take part in code reviews and architecture decisions, and help hold the engineering standard
• Support environment setup and infrastructure-as-code with DevOps on AWS
• Join sprint planning, stand-ups and technical discussions with the client

Required profile

• 4+ years of backend development with strong C# / .NET (ASP.NET Core.NET 6+)
• Solid grasp of clean architecture: DDD, CQRS, repository pattern, dependency injection
• Experience building and integrating REST APIs, including OpenAPI / Swagger
• Brownfield experience: plugging new services into existing systems
• Strong written and spoken English; Agile/Scrum with Jira

Required skills

• AWS: Lambda, SQS, S3, RDS or DynamoDB
• Relational (PostgreSQL or SQL Server) and NoSQL (MongoDB) databases
• JWT / OAuth 2.0 authentication
• Docker and containerized workflows
• Nice to have: retail, e-commerce or B2B commerce experience; event-driven architecture (EventBridge, RabbitMQ); Keycloak and multi-realm identity management; EF Core with Npgsql; promotional products or print-on-demand domain knowledge