Senior Software Engineer – C#/.NET

Description

Location: Warsaw, Poland (Hybrid, 2–3 days per week onsite) About the Role You will work on a mature, commercially successful product while contributing to its ongoing evolution. A significant part of the work involves building new functionality, improving scalability and reliability, and helping modernize selected components into a modern C#/.NET architecture. This position is ideal for engineers who enjoy solving challenging technical problems, taking ownership of features from concept to production, and troubleshooting complex issues in real-world environments. What You'll Do Design, develop, test, and maintain backend services and applications using C# and.NET. Take ownership of complex features throughout the full software development lifecycle. Collaborate with product managers, engineers, and other stakeholders to deliver high-quality solutions. Participate in technical design discussions and evaluate architectural trade-offs. Investigate and resolve production issues using logs, telemetry, diagnostics, and root-cause analysis techniques. Improve system reliability, performance, maintainability, and supportability. Contribute to code reviews and engineering best practices. Support modernization initiatives, including migration of selected legacy components to C#/.NET. Help drive high standards for quality, testing, and software craftsmanship. What We're Looking For Required Qualifications Strong professional experience developing backend applications with C# and.NET. Proven experience owning and delivering complex software features from design through release. Experience working on large-scale commercial products rather than only isolated services or short-term projects. Strong debugging and troubleshooting skills. Solid understanding of software engineering principles, including:Concurrency and multithreadingNetworking fundamentalsTesting strategiesReliability and maintainabilityPerformance optimization Concurrency and multithreading Networking fundamentals Testing strategies Reliability and maintainability Performance optimization Ability to work independently while collaborating effectively within a team. Strong problem-solving and communication skills. Preferred Qualifications Experience modernizing legacy systems or migrating applications to newer technologies. Exposure to customer-hosted, on-premises, infrastructure, storage, backup, endpoint, or systems-management products. Experience integrating with cloud platforms such as AWS or Microsoft Azure. Knowledge of distributed systems, infrastructure software, or storage technologies. Working Environment Hybrid working model based in Warsaw. Collaborative engineering culture focused on ownership, quality, and continuous improvement. Opportunity to contribute to a mature product while shaping its future evolution. Exposure to challenging technical problems and real-world production environments. What Success Looks Like In this role, you will: Deliver high-quality features that provide measurable customer value. Demonstrate strong technical judgment and ownership. Improve product reliability, performance, and maintainability. Effectively diagnose and resolve complex production issues. Contribute to engineering excellence through collaboration, reviews, and knowledge sharing. Support modernization efforts that help evolve the platform for future growth. AI and Engineering Excellence We value engineers who use AI thoughtfully and responsibly to improve productivity, accelerate learning, and support decision-making. Success in this role is not defined by experience with any specific AI tool, but by your ability to apply sound judgment, validate outputs, maintain security standards, and leverage technology effectively to solve problems. This role is best suited for a senior individual contributor who enjoys hands-on engineering, technical ownership, and delivering meaningful product outcomes in a complex software environment. What you need to do now If you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or call us now. Hays Poland sp. z o.o. is an employment agency registered in a registry kept by Marshal of the Mazowieckie Voivodeship under the number 361.

Responsibilities

• For our client we are looking for a Senior Software Engineer to join a product engineering team developing enterprise-grade software used by organizations worldwide. This is a backend-focused role where you will design, build, and enhance complex product capabilities that support administration, automation, reporting, and system management workflows.

Informacje dodatkowe

• Nr ref.: 1201230

• Lokalizacja: Warszawa

• Rodzaj pracy: Stała