Senior Fullstack Developer

Senior Fullstack Developer
In Cobalt Streamworks we work with top international IT companies in order to boost their potential in delivering outstanding, cutting-edge technologies that shape the world of the future. We are currently looking for an experienced Senior Fullstack Developer to join an international team responsible for developing and maintaining modern, secure, and scalable applications supporting critical business processes. You will work in a hands-on development role across both backend and frontend technologies, contributing to high-quality software delivery while collaborating with international stakeholders in an English-speaking environment.
Project information:
– Type of project: Product Development
– Office location: Warsaw, Poland
– Work mode: Hybrid (3 days from the office, 2 days remotely)
– Budget: 100- 130 PLN net/ h- B2B
– Project length: Long-term
– Only candidates with citizenship in the European Union and residence in Poland
– Start date: ASAP (depending on candidate’s availability)
Project scope:
– Design, develop, and maintain modern fullstack applications
– Build secure, scalable, maintainable, and testable software aligned with business requirements
– Develop and evolve Java-based microservices using Spring Boot
– Design and implement modern Single Page Applications (SPA) following frontend best practices
– Collaborate closely with business and technical stakeholders to translate requirements into high-quality technical solutions
– Ensure application reliability, performance, and service continuity
– Follow software engineering best practices, including code quality, testing, and security standards
– Participate in code reviews and contribute to continuous improvement initiatives
– Work within Agile development teams in an international English-speaking environment
– Support the evolution of existing applications while contributing to the development of new features and services
Competence demands:
– 10+ years of professional experience in software development
– Strong experience as a full-stack developer with expertise in backend and frontend development
– Excellent knowledge of Java and Spring Boot
– Proven experience developing microservices-based applications
– Strong experience with modern frontend technologies and Single Page Applications (SPA)
– Experience designing secure, scalable, and high-performance applications
– Solid understanding of software engineering best practices, including testing, code quality, and clean architecture
– Experience working in Agile development environments
– Strong analytical and problem-solving skills
– Excellent communication skills and ability to collaborate with business and technical stakeholders
– Very good English skills
Nice to have:
– Experience with cloud platforms
– Knowledge of CI/CD pipelines and DevOps practices
– Experience with containerization technologies such as Docker and Kubernetes
– Experience working in international enterprise environments
We offer:
– Hybrid working model
– Full-time job agreement based on b2b
– Private medical care with dental care (covering 70% of costs)
– Multisport card (also for an accompanying person)
– Life inssurance
Recruitment process:
– Introductory call
– Technical interview
– Final decision