Backend Software Developer (C#) w Łódź, Polska

Responsibilities

• Lead backend development and technical delivery of a cloud-native microservices platform.
• Design, develop, and maintain scalable backend services using C# and .NET
• Manage AWS-based infrastructure, including ECS, Lambda, Cognito, and supporting services.
• Participate in and coordinate vendor transition and knowledge transfer activities.
• Lead structured codebase handover sessions with the outgoing vendor.
• Own architecture documentation and knowledge transfer workshops.
• Ensure full understanding of all backend services, deployment pipelines, and infrastructure components.
• Develop and maintain Infrastructure as Code using Terraform.
• Build, optimize, and support ETL processes and data pipelines using Python.
• Maintain and improve CI/CD processes using GitHub Actions.
• Collaborate with stakeholders, architects, and development teams to deliver business requirements.
• Ensure platform reliability, security, performance, and maintainability.

Benefits

• Motivizer Benefits Platform to choose and manage all your benefits in one place. You receive a budget (550 PLN monthly). You can choose medical care package, meal tickets, sports cards (we have Multisport and on preferential terms, we have membership cards to one of the most popular Gyms), cinema tickets, shop vouchers, discounts and many more.
• Language Courses – you'll have access to a multi-language learning platform enabling you to practice you language skills and learn new ones!
• Regular and systematic further training opportunities - both internally and from external providers. We support your ongoing learning and development.
• Cooperation within an internal community is our everyday reality. We have networking events, coding challenges, and company parties for different occasions.

Qualifications

• Degree in Computer Science, Engineering, or related field.
• 4+ years of backend software development experience.
• 2+ years in a Senior Engineer role.
• Proven hands-on experience working with AWS cloud services in production environments.
• Experience leading technical teams and driving delivery in complex projects.
• Strong understanding of microservices, distributed systems, and cloud-native architecture.
• Experience managing vendor transitions, system onboarding, or large-scale knowledge transfer initiatives is a strong advantage.
• Ability to work effectively in ambiguous environments and quickly gain ownership of existing systems.
• Strong communication and stakeholder management skills.
• Very good knowledge of English and Polish.
• Openness to visit office once a month.

About Machine Learning Reply

Machine Learning Reply offers customized end-to-end Data Science solutions, covering the entire project life cycle – from initial strategy consulting, data architecture and infrastructure topics, to processing data with quality assurance using Machine Learning algorithms. Machine Learning Reply has extensive expertise in the field of Data Science in all key industries of German HDAX companies.

Machine Learning Reply empowers clients to successfully introduce new data-driven business models and to optimize existing processes and products – with a focus on distributed open source and cloud technologies. With the Machine Learning Incubator, the company offers a program to train the next generation of decision-makers, data scientists and engineers.