Software Engineer (.NET Core / .NET Framework) Role Overview FromHays, we are looking for aSoftware Engineerto join a highly technical team working onperformance optimization ,critical environments, and a majormigration from .NET Framework to .NET Core. In this role, you will design, develop, optimize, and maintain high‐performance services and APIs while contributing to architectural evolution, observability, distributed cache optimization, and 3rd‐line production support when required.Job Details Work Model:Hybrid (2–3 days/week on‐site) Location:Lisbon Industry:Banking & Financial Services Languages:English (B2 or Higher) Salary: Staff Contract:up to €26,500 gross/year Freelance:up to €3,500 gross/month + VAT️Responsibilities Develop, test, and implement new features using.NET Core / .NET Framework. Actively contribute totechnical design decisionsandarchitecture evolution. Participate in themigrationfrom .NET Framework to .NET Core. OptimizeSQL queries, reduce latency, and improve API response times. Create and maintainNuGet packages. Optimizedistributed cacheand databases, including detailed profiling. Implement and maintainobservability(OpenTelemetry, OpenSearch, Prometheus). Ensure secure, clean, and high‐quality code. Provide3rd‐line supportfor production incidents when required.Key Requirements +3 years of experience as a Software Engineer Strong experience with C#, .NET Core, and .NET Framework Advanced SQL and Microsoft SQL Server expertise, including query optimization Proven experience with high‐performance applications (multi‐threading, garbage collection, profiling) Knowledge of distributed caching, preferablyOracle Coherence Fluent in English (B2 level)Ready for the next step? If you're looking for a technically challenging opportunity in a high‐impact environment, apply now, we'll reach out to share more details!