Senior Backend Developer/Senior Software Engineer

🏢 Summary: Senior Backend Developer role focused on building scalable, cloud-native microservices using TypeScript and Node.js in AWS environments. The position involves designing secure backend solutions, developing IAM services, implementing test automation, and deploying distributed systems in a CI/CD setup. Work includes close collaboration within agile teams on modern, serverless architectures. 🗂️ Requirements: Minimum 5 years backend/full stack development experience, Strong experience with TypeScript and NodeJS, Experience with Java or Python, Experience designing microservices and distributed systems, Hands-on experience with AWS serverless services, Experience with automated testing including integration and E2E tests, Experience with CI/CD pipelines, Knowledge of OAuth2, OIDC, JWT, Experience with Infrastructure as Code, Fluent Polish and English 📃 Skills: TypeScript, NodeJS, Java, Python, AWS, Lambda, APIGateway, DynamoDB, EventBridge, S3, SNS, SQS, Microservices, OAuth2, OIDC, JWT, Jest, Postman, Playwright, GitLab, Kubernetes, CDK, Terraform, Serverless, CI/CD 🏢 Description: 🚀 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 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!

🏢 Summary: Full Stack Developer role focused on building and maintaining scalable, cloud-based applications for enterprise data exchange with external government systems. The position involves developing Java (Spring Boot) services, REST APIs, frontend components, and data synchronization processes within a microservices architecture. It includes working in an Agile team and contributing to CI/CD pipelines and automated testing. 🗂️ Requirements: 3+ years experience as Full Stack Developer, Strong proficiency in Java, Experience with Spring Boot, Experience with REST APIs, Experience with microservices architecture, Experience with relational databases, Experience with PostgreSQL, Experience with Node.js, Experience with modern frontend frameworks, Experience with React, Familiarity with CI/CD pipelines, Experience with GitLab CI, Experience with event-driven systems or messaging solutions, Familiarity with AWS, Experience in Agile/Scrum teams 📃 Skills: Java, Spring, SpringBoot, REST, Microservices, PostgreSQL, SQL, Node.js, JavaScript, TypeScript, React, AWS, Git, GitLab, CI/CD, Messaging, Scrum 🏢 Description: 🚀 Java Full Stack Developer (Maternity Cover) Location: Poland - Hybrid (Kraków) 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 Kolomolo is looking for a Java Full Stack Developer to join an international project team delivering modern digital services for a large-scale, enterprise environment. This is a maternity cover position , offering the opportunity to work on high-impact systems, collaborate with senior engineers, and contribute to the development and maintenance of scalable applications. You will be working on a platform responsible for exchanging operational data between our product and external government systems. The solution enables: Two-way data synchronization (both manual and automated) Visibility into pending work items Access to historical records Validation of both system-generated and manually entered data This is a full-stack role with a strong focus on Java, offering the opportunity to work across the entire application and contribute to its evolution. You will be involved in both backend and frontend development, working within a cloud-based architecture and Agile delivery model. What You’ll Be Doing Designing, building, and maintaining application services and APIs using Java (Spring Boot) Developing and enhancing data synchronization processes and system integrations Extending and maintaining existing application components Ensuring performance, scalability, and reliability of the system Contributing to CI/CD pipelines and deployment processes Writing and maintaining automated tests (unit and integration) Collaborating across the application stack to deliver cohesive solutions Tech Stack Frontend: JavaScript / TypeScript, React (or similar) Backend: Node.js Cloud: AWS (preferred) Architecture: Microservices Tools: Git, CI/CD pipelines, modern testing frameworks What We Are Looking For 3+ years of experience as a Full Stack Developer. Strong proficiency in Java. Experience with REST APIs and microservices architecture. Experience with relational databases (e.g., PostgreSQL) Familiarity with CI/CD pipelines (e.g., GitLab CI) Experience with event-driven systems or messaging solutions Strong grasp of software design, scalability, and performance principles Experience with Node.js on the backend. Experience with modern frontend frameworks (e.g., React). Understanding of REST APIs and web services. Familiarity with cloud environments (AWS preferred). Experience working in Agile/Scrum teams. Strong problem-solving skills and attention to detail. Good communication skills in an international environment. Nice to Have Experience with serverless architecture Knowledge of microservices-based systems Experience with automated testing (unit/integration) Exposure to DevOps practices and CI/CD 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. B2B contract or Contract of Mandate (Umowa Zlecenie). 🌟 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!

🏢 Summary: Junior Back-End Developer role focused on building and enhancing production-level microservices within a modern, cloud-based gaming platform stack. The position involves working with Java and Spring Boot in a microservices architecture, ensuring observability and scalability of backend services. It offers hands-on experience with cutting-edge infrastructure and cloud technologies in a collaborative environment. 🗂️ Requirements: Minimum 1 year experience with Java, Solid understanding of backend web development, Knowledge of data structures and algorithms, Ability to develop and maintain microservices, Understanding of REST or RPC-based communication, Experience with containerized environments, Ability to work with relational databases 📃 Skills: Java, Spring, SpringBoot, Microservices, Kubernetes, Docker, Redis, PostgreSQL, Kafka, AWS, GCP, gRPC, Grafana, Alertmanager 🏢 Description: Kickstart your career at our Krakow Studio! At Kalamba Games, we're building the most high-performing stack in the industry across Game Development, RGS Platform, QA, and Art. Based in Krakow, our studio is home to a fun-loving, agile, and experienced team driven by a passion to disrupt the market through cutting-edge technology. We're all about collaboration, innovation, and having a great time while doing amazing work. If you're looking for a place to grow, learn, and make an impact from day one—read on! We're hiring: Junior Back-End Developer (immediate start) Are you a natural problem solver? Do you enjoy diving into new tech and tackling challenges head-on? We're looking for a motivated Junior Back-End Developer to join our growing team. What you'll be working with You'll be hands-on with some of the latest and greatest technologies in the industry: Languages & frameworks: Java 21, Spring Boot, Microservices architecture Infrastructure: Kubernetes, Docker, Redis, PostgreSQL, Kafka Cloud platforms: AWS, Google Cloud Platform Communication & observability: gRPC, Grafana, Alertmanager What you'll do Work on meaningful, production-level tasks that directly impact our products. Develop new microservices and enhance existing ones. Make your services observable with custom dashboards and alert rules. Learn fast and tackle unfamiliar tasks with curiosity and independence. And most importantly—have fun doing it! What we're looking for At least 1 year of experience with Java. Solid understanding of backend web development. Knowledge of data structures, algorithms, and problem-solving fundamentals. Passion, motivation, and eagerness to grow in a collaborative environment. What You'll Get as a Kalambian Employment contract or B2B — your choice 26 days of vacation (regardless of seniority) 1 additional paid day off for each year you're with us Private healthcare Subsidized MultiSport card Flexible working hours and remote work options Game room , snacks, and a fully-equipped kitchen Hybrid work model: We'd love to see you in our Kraków office at least 4 days a week during your first 3 months Let's build something great together If you're ready to take your career to the next level and be part of something exciting, we want to hear from you. Join us and help shape the future of gaming tech—one line of code at a time. Apply now and let's get the ball rolling!

🏢 Summary: Full-time Software Engineer role focused on building secure, scalable backend systems and APIs on AWS using TypeScript. The position involves end-to-end ownership of automated systems that detect misuse and enforce platform policies, working across the full development lifecycle. Ideal for engineers passionate about backend stability, cloud architecture, and high-quality code. 🗂️ Requirements: 3+ years of professional backend development experience, Strong proficiency in JavaScript, TypeScript, and Node.js, Experience building and consuming RESTful or GraphQL APIs, Experience with core AWS services (Lambda, SQS, SNS, API Gateway, S3), Experience with Docker containerization, Experience with NoSQL or relational databases, Understanding of web security principles and best practices, Upper-intermediate or higher English level 📃 Skills: JavaScript, TypeScript, Node.js, AWS, Lambda, SQS, SNS, APIGateway, S3, REST, GraphQL, Docker, MongoDB, DynamoDB, PostgreSQL, Security, CI/CD, Jenkins, GitLab, GitHubActions, React, CloudWatch, Datadog, .NET, Python, GCP, BigQuery 🏢 Description: Salary range: B2B - 30 E/h + VAT 💰 Ciklum is looking for a Software Engineer to join our team full-time in Poland. We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts and product owners, we engineer technology that redefines industries and shapes the way people live. About the role: As a Software Engineer, you will be part of a cross-functional team with full ownership of the product and codebase. You will join a team specifically focused on businesses, building automated systems that detect misuse and enforce platform policies. You will participate in all stages of the development lifecycle: from ideation and design to implementation, deployment, and maintenance. This role is ideal for an engineer with a strong passion for backend stability and scalability who enjoys building robust cloud architectures. Responsibilities: Develop and maintain secure, scalable APIs and services on AWS using TypeScript Write clean, efficient, and testable code for both backend and frontend applications Collaborate closely with senior engineers, product managers, and designers to translate requirements into technical solutions Implement security best practices in your code to protect user data and ensure platform integrity Contribute to the entire development lifecycle, from planning and implementation to deployment and maintenance Troubleshoot, debug, and upgrade existing software to enhance functionality and performance Participate actively in code reviews, providing and receiving constructive feedback to maintain a high-quality codebase Requirements: 3+ years of professional experience in backend development Strong proficiency with JavaScript, TypeScript and Node.js Experience building and consuming RESTful or GraphQL APIs Experience with core AWS services (e.g., Lambda, SQS, SNS, API Gateway, S3) Familiarity with containerization using Docker Experience with NoSQL (e.g., MongoDB, DynamoDB) and/or relational (e.g., PostgreSQL) databases A good understanding of web security principles and best practices Strong problem-solving skills and a passion for writing quality code Upper-intermediate or higher level of spoken and written English Desirable: Hands-on expertise with React Familiarity with CI/CD practices and tools (e.g., Jenkins, GitLab CI, GitHub Actions) Experience with monitoring and logging tools (e.g., CloudWatch, Datadog) Working experience with .Net or Python is a plus Experience with GCP and services like BigQuery Personal skills: Accountability: You take ownership and follow through on your responsibilities Drive: You're proactive and results-oriented, always seeking better ways to solve problems Self-development: You stay curious, seek feedback, and aim for continuous improvement Effective communication: You communicate your ideas clearly and collaborate effectively in a team Mentoring: You're open to helping less experienced team members and sharing knowledge What`s in it for you? Strong community: Work alongside top professionals in a friendly, open-door environment Growth focus: Take on large-scale projects with a global impact and expand your expertise Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies Flexibility: Enjoy flexibility – full remote working possibilities Care: We’ve got you covered with company-paid medical insurance, mental health support, and financial & legal consultations About us: At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress. With delivery centers in Wrocław and Gdańsk, our 300+ professionals in Poland drive forward-thinking solutions for global clients. Join a community where collaboration sparks innovation—and your impact reaches millions. Want to learn more about us? Follow us on Instagram , Facebook , LinkedIn . Explore, empower, engineer with Ciklum! Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum.

🏢 Summary: Full-time Senior JavaScript Engineer role focused on building and evolving a scalable Design System for a global consumer platform. The position involves owning complex frontend features, creating reusable UI components, and ensuring accessibility and high-quality architecture. You will work cross-functionally with UX and product teams to deliver robust, documented, and versioned frontend solutions. 🗂️ Requirements: 5+ years frontend web development experience, Advanced proficiency in React, Advanced proficiency in TypeScript, Advanced proficiency in CSS, Experience building scalable libraries or modular UI components, Experience with Design Systems, Knowledge of WCAG 2.1/2.2 accessibility standards, Experience with versioned code libraries and release management, Upper-intermediate English proficiency 📃 Skills: JavaScript, React, TypeScript, CSS, Next.js, SASS, Playwright, Node.js, MongoDB, AWS, CI/CD, WCAG, Figma 🏢 Description: Salary range: B2B - 40-43 E/h + VAT 💰 Ciklum is looking for a Senior JavaScript Engineer to join our team full-time in Poland. We are a custom product engineering company that supports both multinational organizations and scaling startups to solve their most complex business challenges. With a global team of over 4,000 highly skilled developers, consultants, analysts and product owners, we engineer technology that redefines industries and shapes the way people live. About the role: As a Senior JavaScript Engineer, become a part of a cross-functional development team engineering experiences of tomorrow. You will join a high-impact Design Systems team alongside other Senior Engineers to own high-impact workstreams and cross-functional partnerships. Our goal is to provide a seamless experience for millions of users on a global consumer review platform through robust, documented, and accessible UI patterns. You will operate with high autonomy, turning initial product needs into reusable components that enable product teams to move faster and more consistently. Responsibilities: Feature Ownership: Take end-to-end ownership of complex system features such as Data Visualization suites, theme engines, or complex search/filtering patterns System Architecture: Build for flexibility and reusability, ensuring features solve problems for multiple product teams without creating maintenance bottlenecks UX Collaboration: Work in close partnership with UX designers to bridge the gap between Figma and code, ensuring technical feasibility during design reviews Product Integration: Act as the dedicated technical point of contact for product areas to identify patterns that should be integrated into the core library Accessibility Standards: Own the accessibility (A11y) for your features, ensuring components meet WCAG 2.1/2.2 standards Release Management: Manage the lifecycle of features within a versioned code library, ensuring safe releases and clear migration paths Technical Documentation: Produce clear, comprehensive documentation so that stakeholders, engineers, and AI agents can understand and extend your work Mentorship: Participate in code reviews and RFCs, providing constructive feedback to help other engineers grow while maintaining a high quality bar Requirements: Core Expertise: Advanced, hands-on proficiency with React, TypeScript, and CSS Frontend Experience: 5+ years of professional experience in frontend web development Systems Thinking: Proven experience building scalable libraries, shared infrastructure, or modular UI components Inclusivity: Strong understanding of building accessible interfaces and applying WCAG standards Strategic Execution: Ability to take vague requests, break them down into manageable tracks, and deliver at a steady, predictable pace Communication: Upper-intermediate or higher level of spoken and written English Desirable: Design Systems: Proven experience contributing to a professional Design System or a major open-source project Modern Tooling: Experience with Next.js, CSS Modules, SASS, or Styled Components Testing: Familiarity with end-to-end testing frameworks like Playwright Infrastructure: Understanding of AWS cloud infrastructure or CI/CD practices Backend: Exposure to Node.js, MongoDB Personal skills: Accountability: You take ownership and follow through on your responsibilities Drive: You're proactive and results-oriented, always seeking better ways to solve problems Self-development: You stay curious, seek feedback, and aim for continuous improvement Effective communication: You communicate your ideas clearly and collaborate effectively in a team Mentoring: You're open to helping less experienced team members and sharing knowledge What`s in it for you? Strong community: Work alongside top professionals in a friendly, open-door environment Growth focus: Take on large-scale projects with a global impact and expand your expertise Tailored learning: Boost your skills with internal events (meetups, conferences, workshops), Udemy access, language courses, and company-paid certifications Endless opportunities: Explore diverse domains through internal mobility, finding the best fit to gain hands-on experience with cutting-edge technologies Flexibility: Enjoy flexibility – full remote working possibilities Care: We’ve got you covered with company-paid medical insurance, mental health support, and financial & legal consultations About us: At Ciklum, we are always exploring innovations, empowering each other to achieve more, and engineering solutions that matter. With us, you’ll work with cutting-edge technologies, contribute to impactful projects, and be part of a One Team culture that values collaboration and progress. With delivery centers in Wrocław and Gdańsk, our 300+ professionals in Poland drive forward-thinking solutions for global clients. Join a community where collaboration sparks innovation—and your impact reaches millions. Want to learn more about us? Follow us on Instagram , Facebook , LinkedIn . Explore, empower, engineer with Ciklum! Interested already? We would love to get to know you! Submit your application. We can’t wait to see you at Ciklum.