Middle Java Backend Developer – GenAI

Location: Warsaw, Poland
Work Model: Hybrid – 1–3 days per week from the client office
Contract Type: B2B Contract

About the Role

We are looking for a Mid-Level Java Developer / Java Backend Developer with experience in modern backend engineering and AI-assisted software development to join a high-performing engineering team delivering scalable, secure, and modern Java-based applications and services for a leading global client.

This is a hands-on development role suited to an experienced Java engineer with strong expertise in Java, Spring, REST APIs, microservices, databases, containers, CI/CD, and AI-assisted development tools.

You will be responsible for designing, developing, testing, and supporting reliable software solutions while working closely with cross-functional teams in an Agile/Scrum environment.

Key Requirements

• 5+ years of professional experience working with Java and related technologies.

• Strong hands-on experience with:

  • Java / J2EE

  • REST APIs

  • Spring / Spring MVC

  • JPA / Hibernate

• Experience designing and developing secure, reliable, scalable, and high-performance APIs.

• Strong database knowledge, including Oracle, MySQL, and at least one NoSQL database.

• Practical experience with microservices architecture and distributed systems.

• Hands-on experience with Docker and Kubernetes or similar technologies.

• Experience with:

  • Git

  • Maven

  • Artifactory

  • Jenkins

  • CI/CD

• Experience with application monitoring and log-analysis tools such as Splunk, Humio, or equivalent.

• Strong ability to write clean, maintainable, testable, and well-structured Java code.

• Experience working in an Agile/Scrum environment.

• Hands-on experience with AI-assisted development tools, such as:

  • Claude

  • Cline

  • GitHub Copilot

  • Similar AI coding tools

• Strong communication and collaboration skills.

• Strong sense of ownership for quality, delivery, and production stability.

Key Responsibilities

• Design, develop, test, and maintain scalable Java backend applications and services.

• Develop and maintain REST APIs and microservices.

• Build and support distributed applications using modern software architecture principles.

• Work with Docker, Kubernetes, and containerized environments.

• Participate in system design, code reviews, troubleshooting, and performance optimization.

• Develop and maintain CI/CD pipelines and deployment automation.

• Support production applications, including log analysis, troubleshooting, and incident resolution.

• Apply best practices around unit testing, code quality, security, and maintainability.

• Use AI-powered development tools to improve developer productivity, code quality, and delivery efficiency.

• Identify opportunities for automation and continuous improvement.

• Collaborate with cross-functional teams in an Agile/Scrum environment.

• Take ownership of technical deliverables and ensure timely, high-quality delivery.

Ideal Candidate Profile

The ideal candidate is a hands-on Java Backend Developer with strong experience in enterprise application development, microservices, APIs, databases, containers, CI/CD, and production support.

Experience with GenAI and AI-assisted development tools is an important part of the role. You should be comfortable using tools such as GitHub Copilot, Claude, Cline, or similar solutions as part of your software development workflow.

You will be expected to take ownership of technical deliverables, solve complex engineering problems, contribute to system design and code reviews, and work effectively within a fast-paced Agile engineering team.