Senior .NET Developer

Description

Summary: We are seeking a Senior .NET Developer to design, develop, and evolve robust backend systems, working across both legacy and modern .NET environments. Highlights: 1. Contribute to the design, development, and evolution of robust backend systems 2. Modernize existing logic and integrate with external systems 3. Ensure performance, reliability, and maintainability of applications ### **Job Information** Date Opened 01/04/2026 Job Type Full time City Lisboa Province Lisboa Country Portugal Postal Code 1200\-629 Industry IT Services ### **Job Description** We are looking for a **Senior .NET Developer** to join our team and contribute to the design, development, and evolution of robust backend systems. In this role, you will work across both **legacy and modern .NET environments**, building scalable APIs, integrating with external systems, and helping modernize existing logic. You will play a key role in ensuring **performance, reliability, and maintainability**, while contributing to technical decisions and continuous improvement. ### **Responsibilities** #### **Backend Development** * Develop and maintain backend applications using **.NET Framework and .NET 6\+ (C\#)**. * Design, build, and evolve **RESTful APIs (WebAPI)**, ensuring performance and reliability. * Implement integrations with external systems using **REST, SOAP, and messaging systems (RabbitMQ)**. * Apply best practices in object\-oriented programming and clean, maintainable code. #### **Data \& Performance** * Work extensively with **SQL Server**, including SQL and **T\-SQL development**. * Optimize queries and database performance to ensure efficient data processing. * Contribute to the **modernization of existing logic**, including migration from T\-SQL to C\# where appropriate. #### **Monitoring \& Operations** * Monitor and diagnose applications using **Azure Application Insights**. * Support production environments, handling incidents and ensuring system stability. * Troubleshoot issues and implement long\-term improvements to enhance reliability. #### **Architecture \& Continuous Improvement** * Contribute to **technical design and architectural decisions**. * Promote best practices, coding standards, and performance optimization. * Collaborate with cross\-functional teams to deliver high\-quality solutions. * Continuously identify opportunities for improvement in systems and processes. ### **Requirements** * **6\+ years of experience** in .NET development (both .NET Framework and .NET). * Strong expertise in **C\# and Transact\-SQL (T\-SQL)**. * Solid understanding of **object\-oriented programming (OOP)** and principles such as **SOLID**. * Proven experience with **WebAPI, REST, and SOAP services**. * Hands\-on experience with **messaging systems**, particularly **RabbitMQ**. * Strong knowledge of **SQL Server**, including performance tuning and query optimization. * Experience with **Azure**, especially **Azure Web Apps and Application Insights**. * Good understanding of development best practices and design patterns. * Ability to work **autonomously** and take ownership of solutions. ### **Nice\-to\-have** * Experience with application modernization and legacy system transformation. * Familiarity with CI/CD pipelines and DevOps practices. * Exposure to distributed systems and scalable architectures. If this sounds like you, share your CV with us and let’s talk!