Senior Fullstack .NET Developer with React Expertise

Unleash innovative web solutions — shape the future of digital banking experiences!

Łódź-based opportunity with hybrid work model (2 days in the office/month).

As a Senior Fullstack .NET Developer (React), you will be working for our client, a leading financial institution focused on delivering innovative digital banking solutions. You will join a strategic modernization initiative involving the redevelopment of a business process management platform. The project focuses on rebuilding legacy applications from .NET Framework to modern .NET technologies, migrating infrastructure from on-premises environments to Kubernetes, and implementing high-quality engineering practices. You will collaborate closely with AI-powered development tools, contribute to system design decisions, and help deliver scalable, secure, and maintainable solutions in a complex enterprise environment.

Your main responsibilities:

• Develop and maintain backend services using .NET and C#
• Rebuild legacy applications from .NET Framework to modern .NET architecture
• Design and implement frontend components using React
• Create and maintain automated unit and regression tests
• Collaborate with business stakeholders to analyze and refine requirements
• Design scalable and maintainable software solutions
• Integrate applications with databases and external services
• Utilize LLM-based tools such as Claude and Codex to support software development activities
• Participate in code reviews and ensure adherence to development standards
• Deploy and support applications running in Kubernetes environments
• Work closely with cross-functional teams in an Agile delivery model

You're ideal for this role if you have:

• At least 5 years of experience in software development using C# and .NET
• Experience with .NET Framework and modernizing legacy code
• Good knowledge of React 
• Practical experience working with LLM tools such as Claude and Codex
• Strong experience with automated testing
• Hands on experience with Docker and Kubernetes 
• Experience designing and implementing enterprise applications
• Strong knowledge of MS SQL
• Experience using Git, JIRA, and TeamCity
• Ability to work independently while collaborating effectively within a team
• English skills sufficient to write and understand technical documentation

Nice to have:

• Knowledge of message brokers, especially RabbitMQ,