Andres Retamal Lopez

Led a greenfield, high-volume payment gateway for an international hotel group—sole .NET at kickoff, acting Tech Lead and owner from design to production and 24/7 ops. Built Clean/Hexagonal services in .NET8/9 - ASP.NET Core (MVC/Web API + Minimal APIs) with Blazor; data in EF Core + Azure SQL. Integrated 3+ PSPs end-to-end. Delivered CI/CD (Azure DevOps), Docker, Kubernetes (Helm), blue/green and observability. Security: REST, OAuth2/OIDC, Swagger/OpenAPI. Mentored engineers and drove TDD.

Enhanced and maintained banking/energy platforms focused on REST APIs/microservices, database performance, and process automation. Delivered ASP.NET Core + EF Core services with validations and advanced SQL; containerized with Docker across SQL Server/PostgreSQL. Refactored legacy, added Swagger/OpenAPI versioning, automated image/validation workflows, and strengthened API security (I/O validation, error handling, JWT). Agile, end-to-end with stakeholders. Tech: .NET 6/5/3.1, C#

Supported and enhanced internal banking apps (ING & BBVA). Front-line triage under SLAs; delivered fixes and small features. Built/maintained WPF UIs (MVVM, bindings, async/await) to automate document workflows. Refactored legacy Visual Basic and older .NET Core modules to improve stability/testability. Optimized SQL Server queries/SPs; tuned high-volume batches; scheduled/monitored Windows Services. Tech: .NET Core, WPF, VB, SQL Server, Windows Services, LINQ, ADO.NET, Git.