Senior Engineer (.NET & Azure) Contractor - Portugal

We are seeking an experienced Senior .NET and Azure Engineer to join our engineering team on a contract basis. This role is suited to a hands-on engineer who can quickly understand a large, business-critical platform, contribute with minimal ramp-up time, and work effectively across legacy .NET systems, cloud migration initiatives, integrations, test automation, and production support. The successful contractor will be comfortable working in a mature and complex technology environment while helping improve reliability, maintainability, test coverage, performance, and delivery efficiency. Key Responsibilities Design, develop, test, and maintain applications built with C# and the .NET Framework. Deliver enhancements and fixes across ASP.NET MVC, Web API, Windows Services, WCF, messaging, database, and integration components. Support the ongoing migration of systems and workloads to Microsoft Azure. Contribute to architectural and technical decisions relating to cloud migration, application modernization, observability, scalability, and resilience. Work with RavenDB, SQL Server, Redis, MSMQ, and custom data replication processes. Build and maintain integrations with third-party systems, including ERP platforms, SFTP/FTP feeds, email ingestion services, and SOAP APIs. Support document-processing and OCR workflows using LEADTOOLS and Azure Document Intelligence. Improve automated test coverage across unit, integration, end-to-end, regression, and performance testing. Maintain and extend test suites using NUnit, Selenium, SpecFlow, and Playwright. Diagnose production issues using application logs, telemetry, performance monitoring, and distributed system analysis. Contribute to Azure DevOps repositories, build pipelines, deployment processes, and internal NuGet packages. Work closely with developers, testers, product stakeholders, and operational teams to deliver changes safely and efficiently. Review existing code, identify technical risks, and propose pragmatic improvements. Use AI-assisted development tools effectively to accelerate analysis, implementation, testing, documentation, and troubleshooting while maintaining engineering quality. Produce clear technical documentation and communicate progress, risks, and dependencies proactively. Provision and configure production-like environments in Azure; including compute, networking, and the RavenDB/SQL Server/Redis/MSMQ tiers, to support performance testing, load reproduction, and lift-and-shift piloting. Required Skills and Experience Strong commercial experience developing applications in C# and .NET Framework. Strong experience with Microsoft Azure and cloud migration projects. Experience working with ASP.NET MVC 5 and ASP.NET Web API 2. Experience developing or supporting Windows Services. Strong understanding of enterprise application architecture, distributed systems, and integration patterns. Experience with automated testing, including end-to-end or acceptance testing. Hands-on experience with NUnit, Selenium, SpecFlow, or Playwright. Strong SQL skills and commercial experience with Microsoft SQL Server. Experience working with document databases or NoSQL platforms; RavenDB experience is highly desirable. Experience with messaging technologies such as MSMQ or equivalent asynchronous messaging platforms. Experience diagnosing production defects and performance issues in complex systems. Familiarity with CI/CD processes using Azure DevOps, MSBuild, or VSBuild. Ability to work effectively with an established codebase containing legacy and modern components. Ability to become productive quickly with limited supervision. Strong problem-solving, debugging, and analytical skills. Clear written and verbal communication. A pragmatic, delivery-focused approach with strong attention to quality. Highly Desirable Experience RavenDB 6.x, including: Document modelling Per-customer database architectures Lucene indexing Query and index performance optimisation