Senior Fullstack Software Engineer (Java & React)

Job Description

We are looking for a Senior Fullstack Software Engineer (Java & React) to join a team developing a large-scale digital commerce platform based on microservices and micro-frontends.

You will work end-to-end with Java 25, Spring Boot 4, Spring WebFlux, React, TypeScript and Kubernetes, building new features, integrating backend services and helping modernize the existing platform through legacy migration and technical debt reduction.

A key part of the project is AI-driven development, with coding agents and GitHub Copilot becoming part of everyday engineering. We are looking for someone who actively uses AI coding tools and is interested in shaping how they can improve software development.

Main tasks

• Develop and evolve a distributed online platform based on microservices and micro-frontends.

• Take end-to-end ownership of features, working across both backend and frontend within the same service.

• Build and maintain backend services using Java, Spring Boot and Spring WebFlux, including REST APIs and integrations with internal and backend systems.

• Develop frontend functionality using React, TypeScript, JavaScript, HTML and NPM.

• Work with content delivered through a CMS and related content delivery services.

• Implement new platform features and support the migration of legacy applications to the modern architecture.

• Improve the existing codebase through refactoring, technical debt reduction and resolution of long-standing technical issues.

• Contribute to the adoption of new API standards, including TM Forum Open APIs.

• Work with containerized applications using Kubernetes and Docker, including deployment, operation, monitoring and troubleshooting.

• Use AI coding agents and AI-assisted development workflows as part of your daily work and contribute to improving these practices within the team.

• Work on multiple initiatives of different sizes, from short tasks to larger projects.

• Participate in knowledge-transfer activities, keep technical documentation up to date and actively share knowledge with other developers.

Profile

Requirements

• Several years of professional experience in developing modern web applications, with strong backend expertise and the ability to work independently at Senior level.

• Strong practical knowledge of Java 8+ and Spring Boot, as well as REST API design with JSON.

• Familiarity with current versions of the Java/Spring ecosystem and a strong understanding of reactive programming, supported by hands-on experience with Spring WebFlux, Project Reactor or a comparable reactive stack.

• Hands-on frontend experience with React, TypeScript, JavaScript, HTML and NPM, with the confidence to work across frontend and backend within the same service.

• Experience with JUnit, Mockito, WireMock, Git, JPA/Hibernate and XML processing technologies such as XSLT, XPath and XQuery.

• Hands-on experience with Kubernetes and Docker, including deployment, operation, monitoring and troubleshooting of containerized applications in cloud-native environments.

• Experience developing and evolving microservice-based and distributed systems, including working with established, long-running codebases.

• Practical experience with AI-driven software development, for example GitHub Copilot, OpenCode, coding agents, context management, harness engineering or spec-driven development.

• Regular use of AI coding agents in software development, including adapting prompts or skills to your needs and using AI to generate a meaningful part of your code. You should be able to explain how these tools improve your development workflow.

• Ability to take ownership of features from design through production and make sound technical decisions within a distributed architecture.

• A proactive, analytical and quality-oriented approach, with a focus on continuous improvement and practical problem-solving.

• Willingness to challenge existing approaches, contribute your own ideas, review code, share knowledge and support other developers.

• Ability to work effectively in an Agile, distributed and international environment.

• English and Polish, both written and spoken (minimum B2).

Nice to have

• Experience with micro-frontend architectures.

• Knowledge of Helm charts and Jenkins CI/CD pipelines.

• Experience with headless or content-driven systems, particularly NEOS CMS.

• Experience migrating legacy applications to modern platforms.

• Experience with larger refactoring and technical debt reduction initiatives.

• Previous experience working in distributed, multinational and remote teams.

• Knowledge of BDD and test automation beyond unit testing, for example Playwright.

Additional Information

This position offers a hybrid or remote work model. Office location: Warszawa, Poznań, Lublin

Please be advised that we will contact only selected candidates

We hereby inform you that Inetum Polska sp. z o.o. has implemented an internal reporting (whistleblowing) procedure. The content of the procedure and the possibility to submit an internal report are available at: https://inetum.whispli.com/speakup?locale=pl