Senior Backend Developer

🚀 Senior Backend Developer

Location: Kraków, Poland

Experience: 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