Senior Backend Developer

🚀 Senior Backend Developer Location: Kraków, PolandExperience: 5+ years Contract: B2B, Full-Time Join the Future of Digital Tech with Kolomolo At Kolomolo, we don’t just follow trends - we set them. As a global supplier of IT services and digital modernization solutions, we help businesses embrace cutting-edge technology to optimize their operations. Now, we are growing and looking for fresh talent to grow with us. Are you proactive, tech-savvy, and eager to build your career in IT? This role could be your perfect fit. About the Role We’re looking for a Senior Backend Developer who enjoys building reliable, scalable, and modern cloud-native applications. In this role, you’ll be responsible for backend feature development, system modernization, test automation, code refactoring, and production deployments. You’ll work on distributed systems and microservice-based architectures while contributing to the design and development of secure and high-performing backend solutions. This role is ideal for someone who combines strong technical expertise with a collaborative mindset and enjoys working in agile, engineering-driven environments. What You’ll Be Doing • Develop microservices based on Typescript & NodeJS for core business components. • Design and develop company’s internal IAM microservice, preparing for a migration on a new solution. • Design and develop cloud native applications based on AWS services like Lambda, API Gateway, DynamoDB and EventBridge. • Creating and running automated tests, particularly integration tests and end-to-end tests for the backend layer. • Work closely with Architects & SRE to follow security & reliability standards while being  actively involved in architectural discussions. • Work with external partners & vendors while developing various integrations. • Collaborate with the team and drive it while ensuring high code quality and standards. • Be actively involved in designing and developing reliable & secure backend features/functions. • Work with continuously delivered (CI/CD), asynchronous and distributed systems Tech stack • Runtime: Serverless (Lambda, API Gateway, EventBridge) • Backend:  NodeJS / Typescript (additional Java or Python) • Persistency: DynamoDB, S3, SNS, SQS • Architecture: Microservices • IAM: oAuth2, OIDC Connect, JWT, OPAL • CI/CD: GitLab • QA: Playwright/ Postman/ Jest • Infrastructure: AWS, Kubernetes, AWS CDK, Terraform What We Are Looking For • Min. 5 years of experience as a backend/full stack developer, with recent projects in TypeScript & NodeJS and other backend programming language (preferably Java or Python). • Experience in creating and running test automation with holistic approach including system, performance smoke and E2E tests (full testing pyramid) on Jest/Postman/Playwright. • Ability to share your knowledge, experiences, and opinions on the forum via technology demos/brainstorming sessions. • Willingness to grow and learn with a passion for creating new solutions. • Experience in working closely with product and design teams as well as doing pair programming in small, agile, and cross-functional teams. • Ability and openness to work in a team, especially within a culture of mutual respect and continuous feedback. • Being a Team Player, able to help people to grow and guide decision-making processes. • Open minded, communicative and focused on delivering business value . • Fluent verbal and written skills in Polish and English. Nice to Have • Familiarity with Customer Identity Access Management systems & solutions (CIAM), ideally with proven record in designing and implementing. • Experience in Infrastructure as a code especially Terraform/ AWS CDK. • Developing & maintaining team’s monitoring dashboards in Grafana stack (Prometheus, Looki). What is in It for You • Competitive salary and benefits. • Career development opportunities in a growing tech company. • Continuous learning culture: mentorship, internal training, and certifications. • Flexible, agile work environment (remote, hybrid, or on-site in Kraków). • Office perks: great coffee, tea, fresh fruit, snacks, and a fun atmosphere. • Flat management structure, where your voice matters. • Regular team events and a social, supportive work culture. • Independent Contractor. 🌟 Why Join Kolomolo? At Kolomolo, we prioritize innovation, agility, and autonomy. Our teams have the freedom to own their work, share ideas, and make meaningful contributions. Inspired by Scandinavian values, we believe in work-life harmony and creating an inclusive culture where everyone thrives. You will be part of a passionate, skilled, and friendly team that works hard and celebrates together. Here, you can build your career on your own terms, with opportunities to grow, learn, and make a real impact. Our Flat Structure & The Culture of Inclusion At Kolomolo, we break the corporate mold. We offer: • Agile Teams & Autonomy: No micromanagement. You’ll own your projects and enjoy the freedom to innovate. • Work-Life Harmony: Inspired by Scandinavian values, we prioritize balance and flexibility, where remote work and asynchronous collaboration are in our DNA. • Learning & Growth: Continuous learning is at our core. We reward hard work, value smart ideas, and foster an environment of mutual respect and trust. • Inclusive Culture: We believe in DEI: diversity, equity and inclusion. We are committed to creating an environment where every individual, regardless of background, identity, or experience feels valued, respected, and empowered to thrive. Join Kolomolo and elevate your career with cutting-edge technology, a supportive team, and a company that truly values your input. Ready for the next step? Apply now and start an exciting journey of growth and innovation with us!