Java Developer (Energy Sector)

🏢 Summary: B2B contract for a Java Developer in the energy sector, focused on adapting existing BAM services (Opera, STO3) and implementing integration solutions to support migration from the current Exchange Tool. The role involves backend development, system integration, interface creation, testing, and deployment planning in a fully remote setup from July to December 2026. The project emphasizes Java-based technologies and modern containerized environments. 🗂️ Requirements: 4+ years of professional experience in Java development, Proven experience with Spring Boot, Experience with Kotlin, Experience with JavaScript or Typescript, Experience with Angular, Hands-on experience with Docker, Hands-on experience with Kubernetes, Experience with Kafka, Experience with Postgres, Experience designing and implementing system integrations, Ability to create technical documentation and deployment plans, Relevant degree in Computer Science or equivalent, Fluency in English 📃 Skills: Java, Spring, SpringBoot, Kotlin, JavaScript, Typescript, Angular, Docker, Kubernetes, Kafka, Postgres 🏢 Description: Industry: Energy Project duration: from July 1, 2026, to December 31, 2026. Location: 100% remotely Rate: 4-7 years of experience - 155 pln/h on b2b; 7-10 years of experience - up to 185 pln/h on b2b Introduction & Summary: We are seeking a skilled Java Developer to join our team. This role involves the adjustment of existing BAM Services, particularly Opera and STO3, to facilitate the transition from the current Exchange Tool. The ideal candidate will possess a strong background in Java and related technologies with a focus on integration and implementation. Main Responsibilities: The Java Developer will be responsible for the following key tasks: Develop and implement a technical integration concept. Create and maintain interfaces and adapters for PowerBid. Conduct testing and prepare technical documentation. Design a cutover and rollback plan for project deployment. Collaborate with the Product Owner and Solution Architect during the development process. Key Requirements: Proven experience with Java, Spring Boot, and Kotlin. Familiarity with JavaScript/Typescript and Angular. Experience with Docker, Kubernetes, and Kafka. Knowledge of Postgres and Rich Clients. Relevant university degree in Computer Science or an equivalent field. Strong communication skills and an independent working style. Fluency in English; proficiency in German is advantageous. Nice to Have: Experience in requirement engineering. Basic understanding of the energy market in Germany and the Netherlands Understanding of energy market dynamics.

🏢 Summary: Remote B2B role focused on designing and implementing a new integration layer between BAM services and the PowerBid system, replacing the existing Exchange Tool. The position involves developing interfaces, ensuring system compatibility, and executing cutover and rollback strategies in an international energy market environment. You will work with modern backend and container technologies while influencing technical solutions. 🗂️ Requirements: Strong experience with Java, Strong experience with Spring Boot, Strong experience with Kotlin, Experience with Docker, Experience with Kubernetes, Experience with Kafka, Experience with PostgreSQL, Experience with Rich Client applications, Degree in Computer Science or related field, Knowledge of requirement engineering, Fluent English 📃 Skills: Java, SpringBoot, Kotlin, Kafka, Kubernetes, Docker, PostgreSQL, JavaScript, TypeScript, Angular 🏢 Description: Salary: 1000 - 1300 PLN/MD on B2B Work model: Remote Availability: ASAP or within 14 days preferred Why choose this offer? You will work in an international environment , collaborating with teams and stakeholders from different countries. Opportunity to take ownership of the development process and influence the technological direction of the solutions you build. The energy market is in an exciting transition , moving away from fossil fuels towards decentral solutions, renewables, and energy efficiency Project The project focuses on implementing a new integration layer between existing BAM services and the PowerBid system , replacing the current Exchange Tool. It includes designing and developing interfaces/adapters, ensuring system compatibility, and delivering full technical documentation. The work also involves defining and executing a cutover and rollback strategy to ensure a smooth transition. Expected competences and knowledge Strong experience with Java, Spring Boot, and Kotlin Hands-on experience with JavaScript/TypeScript and Angular (nice to have) Experience with Docker and Kubernetes Familiarity with Kafka and Postgres Experience with Rich Client applications Basic knowledge of the energy market in Germany and the Netherlands Degree in Computer Science or a related field Knowledge of requirement engineering Strong communication skills and ability to work independently Fluent English (German is a plus) Technologies you'll work with Java Spring Boot Kotlin Kafka Kubernetes Docker PostgreSQL JavaScript / TypeScript Angular Client – why choose this particular client from the Jit portfolio? Jit Team is cooperating with European energy company with approximately 20 000 employees. For more than 100 years, they have electrified industries, supplied energy to people’s homes and modernized way of living through innovation and cooperation. The purpose is to make fossil-free living possible within one generation . To be able to reach this ambitious goal we are looking for talented individuals who, in addition to their passion for their own role, also have strong team spirit and want to contribute to supporting a meaningful corporate mission. About Jit Team The Human Factor of IT - it’s not just a slogan, it’s a philosophy. The foundation of Jit Team is people, which is why we prioritise you. We employ over 770 experienced experts, to whom we offer developmental projects, a wide range of benefits, and a proprietary professional development programme. Together with clients from around the world, we create innovative IT solutions delivered by highly specialised and efficient teams. Behind our maxim are also charitable and educational activities. We support schools, universities, and educational institutions by conducting workshops, running educational projects, sponsoring events, and donating learning equipment. We offer internships that help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We also support numerous charitable organisations helping people in need, children, and the elderly. We are a Polish company and we share what we have achieved over more than 15 years of activity. By supporting local initiatives, we contribute to the circulation of good energy.

🏢 Summary: Remote B2B Java Developer role focused on developing and enhancing enterprise applications within an agile team. The position involves building, testing, and optimizing Java-based systems under senior guidance while contributing to continuous integration and system maintenance. Long-term cooperation with occasional visits to Germany. 🗂️ Requirements: Fluent German C1, English minimum B1, Bachelor’s degree in Computer Science or equivalent, Minimum 5 years professional experience, Strong knowledge of Java 8+, Minimum 2 years experience with Git, Minimum 2 years experience in Java development projects, Minimum 2 years experience with Spring Boot, Minimum 1 year experience with REST APIs, Minimum 1 year experience with JUnit and Mockito, Strong hands-on experience with Linux, Minimum 1 year experience with Oracle or PostgreSQL, Minimum 1 year experience with Gradle 📃 Skills: Java, SpringBoot, Git, Jira, Confluence, JUnit, Mockito, Linux, Oracle, PostgreSQL, Gradle, REST, React, TypeScript, Scrum 🏢 Description: Mode : remote Contract : B2B Language : German (C1), English (B1) Summary: The Java Developer role primarily focuses on supporting Java-based application development within a collaborative agile team, enhancing enterprise systems under the mentorship of senior developers. Responsibilities: Support Java application development under senior guidance. Collaborate within an agile framework to improve enterprise systems. Utilize Git for version control and project management tools like Jira and Confluence. Participate in coding, testing, and optimizing Java applications. Engage in continuous integration processes and maintain operational environments. Must Haves: Fluent German (C1 level, spoken and written). English skills (minimum B1 level, spoken and written). Bachelor’s degree in Computer Science or equivalent, with at least 5 years of professional experience. Solid theoretical knowledge of Java (minimum version 8). Practical experience with Git (minimum 2 years). Experience in Java development projects (minimum 2 years). Familiarity with Spring Boot (minimum 2 years). Knowledge of RESTful APIs (minimum 1 year). Experience with testing frameworks (JUnit, Mockito) (minimum 1 year). Hands-on experience with Linux (strong command over system functionalities). Experience with databases such as Oracle or PostgreSQL (minimum 1 year). Familiarity with continuous integration using Gradle (minimum 1 year). Nice to Haves: Front-end development experience with React and TypeScript (minimum 1 year). Agile development experience, especially with Scrum (minimum 1 year). Exposure to large-scale public or private sector projects with significant deployment (minimum 1 year). Other Details: Location: Remote within Poland with occasional visits to Germany. Hospitality: Company-provided laptop. Collaboration: Independent work style paired with team collaboration. Duration: Long-term cooperation over 48 months. Decision Timeline: 2-3 months post-May. Documentation: Required copies of diplomas and certifications.

🏢 Summary: Remote B2B offer for an experienced Java Developer to design and build scalable REST APIs and broker integrations using Spring-based technologies within a microservices architecture. The role focuses on high-quality API development, SQL database management, and system design in a Scrum team. The position involves international collaboration and participation in architecture and integration initiatives. 🗂️ Requirements: Minimum 5 years of experience with Java (8/17/21), Strong knowledge of Spring Framework, Strong knowledge of Hibernate, Experience with REST API design and development, Experience with microservices architecture, Strong SQL and relational database expertise, Knowledge of architectural and design patterns, Experience with Git, Experience with TeamCity, Polish proficiency, English proficiency 📃 Skills: Java, Spring, Hibernate, SQL, REST, Microservices, Git, TeamCity, Maven, Scrum, RelationalDatabases, DesignPatterns 🏢 Description: Work model: remote, visit in the office once a quater in Warszawa Rate: up to 150 PLN/h (B2B contract) We are looking for a motivated Java Developer to join our team focused on building and evolving API integrations with external brokers. The ideal candidate will possess a strong background in Java, Spring-based technologies, and a deep understanding of systems integration and microservices architecture. You will contribute significantly to developing high-quality, maintainable APIs that enable seamless integration with various partners across multiple international markets. We work in a cross-functional team utilizing Scrum methodology. Main Responsibilities Design and build high-quality APIs using Java (8/17/21) and Spring-based technologies, ensuring scalability and maintainability. Develop and enhance broker integrations, contributing to business growth and market expansion. Contribute to modern service-oriented architecture design applying microservices knowledge. Manage SQL databases and ensure data consistency and reliability in applications. Utilize tools like Git, Maven, and TeamCity for continuous integration and code delivery. Collaborate on frontend API usability to ensure practical and well-structured solutions. Communicate effectively in Polish and English to facilitate international collaboration. Key Requirements At least 5 years of experience with Java (8/17/21 ) Deep knowledge of the Spring Framework and Hibernate. Strong SQL and relational database expertise. Strong problem-solving skills and proactive attitude. Experience in clean REST API design and development. Familiarity with microservices architecture. Knowledge of architectural and design patterns. Experience with Git and TeamCity. Polish and English proficiency. Nice to Have Experience with React for effective collaboration with frontend developers. Experience with large-scale applications using Maven. Knowledge of Apache Kafka. Experience with Domain-Driven Design (DDD) or Hexagonal architecture. Experience in decoupling monolithic applications. Background in the fintech industry. Recruitment process: 1. Live coding session 2. System design session 3. HR interview

🏢 Summary: B2B opportunity for an experienced Java Developer to build a greenfield loan system (STP) in the banking sector. The role focuses on developing a robust Spring Boot–based platform, integrating via REST and Kafka, and shaping architecture and technical decisions in an Agile environment. Hybrid work model with regular collaboration in Gdańsk. 🗂️ Requirements: 8+ years of commercial experience with Java (version 21+), 8+ years of experience with Spring Boot, 8+ years of experience with JPA, Proficiency with Maven, Experience with Liquibase for database versioning, Experience with REST API integration, Experience with Kafka event streaming, Professional working proficiency in English 📃 Skills: Java, SpringBoot, JPA, Maven, Liquibase, Kafka, REST, Cucumber 🏢 Description: General info: - Industry: banking - Work model: hybrid (min. 2 days in office in Gdańsk) - Rate: 140-160/h net + vat B2B We are seeking experienced Java Developers to join our innovative project, called STP, focusing on a loan system. This exciting greenfield initiative allows you to shape a system from the ground up, supported by a dedicated and engaged business team. Main Responsibilities: Develop and maintain a robust Java platform using Spring Boot Integrate with surrounding systems through REST APIs and Kafka-based event streaming Ensure clean architecture, maintainable code, and clear ownership Utilize AI-assisted development tools to enhance productivity Collaborate closely with Business SMEs and the Product Owner Work in an Agile environment, promoting high levels of collaboration and continuous improvement Participate in solution design and influence technical decisions Key Requirements: Java 21+, with 8+ years of experience Spring Boot, with 8+ years of experience JPA, with 8+ years of experience Maven proficiency Liquibase for database change versioning Nice to Have: Cucumber for testing Other Details: This role is based in Gdańsk, Poland, and requires collaboration in English. Expect a dynamic Agile setup with an emphasis on shared understanding and collaborative solution design.

🏢 Summary: Long-term B2B contract for a Senior Java Developer to design and implement complex Java-based solutions in large-scale enterprise or public sector projects. The role involves technical leadership, mentoring, and working in a fully remote model without business travel. The position requires strong backend expertise and experience with modern Java ecosystems and cloud-native tools. 🗂️ Requirements: Minimum 5 years of professional experience in Java, Strong knowledge of Spring Boot, Experience with RESTful APIs, Experience with JUnit and Mockito, Experience with OpenShift, Experience with Helm, Experience with Spring Data or JPA, Minimum 1 year experience with Oracle or PostgreSQL, Minimum 2 years experience with Gradle, Experience in large-scale enterprise or public sector projects, Degree in Computer Science or equivalent, German C1, English minimum B1 📃 Skills: Java, Spring, SpringBoot, REST, JUnit, Mockito, OpenShift, Helm, JPA, SpringData, Oracle, PostgreSQL, Gradle, SQL 🏢 Description: Summary: The Senior Java Developer plays a crucial role in designing and implementing complex Java-based solutions, mentoring other team members, and contributing to large-scale projects in either the enterprise or public sectors. Remote work model Contract type : B2B, long-term- 48 months Business travels : No Salary Grids: 160-180 zł/h Main Responsibilities: Design and implement complex Java-based solutions. Mentor junior developers and assist in team knowledge sharing. Manage and contribute to large-scale enterprise or public-sector projects. Key Requirements: Fluent in German (C1) and English (min. B1). Degree in Computer Science or equivalent. Minimum of 5 years of professional experience in Java Strong understanding of Spring Boot, RESTful APIs, testing frameworks (JUnit, Mockito) Experience in OpenShift and Helm charts and ORM frameworks like Spring Data or JPA Knowledge of Oracle or PostgreSQL (min. 1 year). Experience with Gradle for continuous integration (min. 2 years). Experience with large public sector projects or comparable private sector engagements. Nice to Have: Additional years of experience with core technologies beyond the stipulated minimum. Frontend experience with React and TypeScript, and understanding of Ajax (min. 1 year). Experience with complex enterprise application integration.

🏢 Summary: Full Stack Java Developer role focused on enhancing and modernizing legacy Java systems to support ISO 20022, while developing and maintaining backend services in a distributed, event-driven environment. The position involves full lifecycle development, from requirements analysis to production releases, in a hybrid work model in Warsaw. 🗂️ Requirements: 4+ years of experience as Java or Full Stack Developer, Strong experience with Java and Spring ecosystem, Hands-on experience with Hibernate and DB2, Experience with Apache Kafka and event-driven architectures, Experience with MongoDB, Experience building RESTful APIs and microservices, Experience with Maven multi-module builds, Experience with Docker, Experience with Git and CI/CD pipelines, Experience working with distributed systems and legacy codebases 📃 Skills: Java, Spring, SpringBoot, SpringData, SpringSecurity, Hibernate, DB2, Kafka, KafkaStreams, KafkaConnect, MongoDB, REST, Microservices, Maven, Docker, Git, GitLab, CICD, ISO20022 🏢 Description: For our Client we are looking for a Full Stack Java Developer. Warsaw, hybrid (4 days per week from the office) B2B: 28,000–35,000 PLN per month Key Responsibilities Gather and analyse requirements with business stakeholders Design, plan, implement and test changes with the engineering team Adapt and enhance legacy Java applications for ISO 20022 changes Develop and maintain backend services and integrations Participate in code reviews, UAT support and production releases Continuously improve code quality and system design Requirements 4+ years of experience as a Java / Full Stack Developer Strong hands-on experience with: Java, Spring, Spring Boot (DI, Spring Data, Spring Security) Hibernate, DB2 Apache Kafka (producers, consumers, Kafka Streams, Kafka Connect) MongoDB (document modelling, Spring Data MongoDB) RESTful APIs, microservices, event‑driven architectures Maven (multi-module builds) Docker Git & CI/CD (GitLab CI preferred) Experience working in distributed systems and complex legacy codebases Strong analytical skills and ability to understand complex business logic Good communication skills and ability to work in a global team

🏢 Summary: Full Stack Java Developer role focused on enhancing and maintaining legacy Java systems in line with ISO 20022 standards while building and supporting modern backend services and integrations. The position involves working on microservices and event-driven architectures within a distributed environment, contributing to the full development lifecycle from requirements analysis to production releases. 🗂️ Requirements: 4+ years experience as Java or Full Stack Developer, Strong hands-on experience with Java, Strong hands-on experience with Spring and Spring Boot, Experience with Hibernate and DB2, Experience with Apache Kafka, Experience with MongoDB, Experience building RESTful APIs and microservices, Experience with event-driven architectures, Experience with Maven multi-module builds, Experience with Docker, Experience with Git and CI/CD pipelines, Experience working with distributed systems, Experience working with complex legacy codebases 📃 Skills: Java, Spring, SpringBoot, Hibernate, DB2, Kafka, MongoDB, REST, Microservices, Maven, Docker, Git, GitLab, CI/CD 🏢 Description: For our Client we are looking for a Full Stack Java Developer. Warsaw, hybrid (4 days per week from the office) B2B: 28,000–35,000 PLN per month Key Responsibilities Gather and analyse requirements with business stakeholders Design, plan, implement and test changes with the engineering team Adapt and enhance legacy Java applications for ISO 20022 changes Develop and maintain backend services and integrations Participate in code reviews, UAT support and production releases Continuously improve code quality and system design Requirements 4+ years of experience as a Java / Full Stack Developer Strong hands-on experience with: Java, Spring, Spring Boot (DI, Spring Data, Spring Security) Hibernate, DB2 Apache Kafka (producers, consumers, Kafka Streams, Kafka Connect) MongoDB (document modelling, Spring Data MongoDB) RESTful APIs, microservices, event‑driven architectures Maven (multi-module builds) Docker Git & CI/CD (GitLab CI preferred) Experience working in distributed systems and complex legacy codebases Strong analytical skills and ability to understand complex business logic Good communication skills and ability to work in a global team

🏢 Summary: B2B Full Stack Java Developer role in Warsaw (hybrid) focused on enhancing legacy Java systems for ISO 20022 compliance and building backend services and integrations. The position involves designing, implementing and testing changes in distributed, event‑driven architectures while collaborating with business stakeholders and global teams. Emphasis is placed on code quality, system design and production support. 🗂️ Requirements: 4+ years experience as Java or Full Stack Developer, Strong hands-on experience with Java, Strong hands-on experience with Spring and Spring Boot, Experience with Hibernate and DB2, Experience with Apache Kafka, Experience with MongoDB, Experience building RESTful APIs and microservices, Experience with event-driven architectures, Experience with Maven multi-module builds, Experience with Docker, Experience with Git and CI/CD, Experience working with distributed systems, Experience working with complex legacy codebases 📃 Skills: Java, Spring, SpringBoot, Hibernate, DB2, Kafka, MongoDB, REST, Microservices, Maven, Docker, Git, GitLab, CI/CD 🏢 Description: For our Client we are looking for a Full Stack Java Developer. Warsaw, hybrid (4 days per week from the office) B2B: 28,000–32,000 PLN per month Your responsibilities Gather and analyse requirements with business stakeholders Design, plan, implement and test changes with the engineering team Adapt and enhance legacy Java applications for ISO 20022 changes Develop and maintain backend services and integrations Participate in code reviews, UAT support and production releases Continuously improve code quality and system design Requirements: 4+ years of experience as a Java / Full Stack Developer Strong hands-on experience with: Java, Spring, Spring Boot (DI, Spring Data, Spring Security) Hibernate, DB2 Apache Kafka (producers, consumers, Kafka Streams, Kafka Connect) MongoDB (document modelling, Spring Data MongoDB) RESTful APIs, microservices, event‑driven architectures Maven (multi-module builds) Docker Git & CI/CD (GitLab CI preferred) Experience working in distributed systems and complex legacy codebases Strong analytical skills and ability to understand complex business logic Good communication skills and ability to work in a global team

🏢 Summary: Long-term B2B hybrid role focused on hands-on Java and React development within a microservices architecture, contributing directly to production code and system design. The position emphasizes high-frequency delivery, REST API development, and collaboration in a global engineering environment. It combines technical leadership with active development in financial-sector projects. 🗂️ Requirements: Strong experience with Java, Strong experience with ReactJS, Experience with microservices architecture, Experience delivering RESTful APIs, Experience with PostgreSQL, Recent experience with modern Java versions, Ability to deliver code changes frequently, Background in banking or financial sector 📃 Skills: Java, ReactJS, Microservices, REST, PostgreSQL, Docker, Kubernetes 🏢 Description: Working mode: Hybrid - 6 days per month at the Kraków office Contract type: B2B, long term cooperation Rate: 200 PLN/h Summary: This role focuses on hands-on development and system architecture, driving engineering culture, and enhancing business growth through technical expertise in a collaborative, global environment. Main Responsibilities: Deliver code to production and support system architecture aligned to microservices Understand business, engineering, and non-functional requirements Drive the desired engineering culture across teams Collaborate with a globally diverse team across regions Proactively remove impediments, assess risks, and communicate issues to program management Identify and eliminate process inefficiencies Key Requirements: Strong Java and React programming experience Experience in microservice architecture Background in the financial sector, particularly banking Proven capability of delivering code changes at high frequency Experience with RESTful API delivery Familiarity with PostgreSQL databases Recent Java experience, preferably with the latest versions Experience with ReactJS for UI application development Nice to Have: Knowledge of containers and orchestration technologies like Docker and Kubernetes. Other Details: This position offers the opportunity to work within a multi-regional team on innovative projects. Ideal for candidates seeking to leverage their development skills in a dynamic and evolving business context.