JVM Software Engineer

🏢 Summary: Long-term B2B opportunity for a senior engineer to deliver production-ready code and shape system architecture in a microservices environment. The role combines hands-on Java and React development with architectural responsibilities in a global, collaborative setup. It focuses on high-frequency delivery and technical excellence within the financial sector. 🗂️ Requirements: Strong Java experience (latest versions), Strong React experience, Experience with microservices architecture, Experience delivering RESTful APIs, Experience with PostgreSQL, Proven high-frequency code delivery, Experience in banking or financial sector 📃 Skills: Java, React, Microservices, REST, PostgreSQL, Banking, Docker, Kubernetes 🏢 Description: Working mode : Hybrid - 6 days per month at the Warsaw 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.

🏢 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.

🏢 Summary: Contract-based role for a Java Developer to build and enhance a microservices-based e-commerce platform, focusing on modules such as product search optimization and order management. Work with modern cloud and container technologies in a hybrid model with limited on-site presence. 🗂️ Requirements: 3+ years of experience with Java, 3+ years of experience with Spring Boot, Experience with microservices architecture, Experience or willingness to work with Kotlin or Golang, Exposure to cloud platforms (preferably GCP), Communicative English (min. B2) 📃 Skills: Java, SpringBoot, PostgreSQL, Docker, Kubernetes, Terraform, GCP, Kotlin, Golang, Microservices 🏢 Description: We’re looking for talented Java Developers to join one of our clients – an international e-commerce company shaping new software engineering team in Poland. Employment terms: Contract of employment Hybrid model – 1 visit/month in the office (company located near Konin, wielkopolskie) In this role you will: Contribute to the development of microservices e-commerce platform with focus on various modules connected with e.g. product search optimization, order management, Work using technologies such as: Java, Spring Boot, PostgreSQL, Docker, Kubernetes, Terraform, GCP, Kotlin, Golang, Collaborate within an international development team. Requirements: Min. 3+ years of experience with Java and Spring Boot, Experience or willingness to expand your expertise by Kotlin/Golang, Exposure to cloud solutions – ideally GCP Communicative English – min. B2. Our Client offers: Benefit package including: private medical care, Multisport, life insurance, studies/courses subsidy, Hybrid type of work – office based near Konin – if you’re located 50+km from the office – 1 visit/month (for 2 days), Opportunities to grow and collaborate within an international environment.

🏢 Summary: Senior Backend Java Developer role in a long-term project building scalable, high-performance backend systems integrated with AWS cloud services. The position focuses on clean architecture, batch processing, and containerized deployments within an agile environment. Opportunity to shape technical decisions while working on a business-critical enterprise system. 🗂️ Requirements: Minimum 8 years of experience in Java backend development, Strong proficiency in Java, Solid knowledge of PostgreSQL, Experience with database optimization, Hands-on experience with Hibernate Criteria API, Experience with Spring Boot, Experience with Spring Batch, Experience with batch processing, Practical knowledge of AWS services (ECS, S3, RDS), Experience with Docker, Knowledge of REST API design, Understanding of clean architecture principles 📃 Skills: Java, Spring, SpringBoot, SpringBatch, Hibernate, PostgreSQL, AWS, ECS, S3, RDS, Docker, REST, SQL, AI 🏢 Description: Salary: 1200 - 1600 pln/md on B2B Hybrid model : hybrid from Gdynia (2 day working from the office, final details to be discussed with the team) Why choose this offer? Be part of a development team working on a long-term project Opportunity to shape technical decisions and best practices from the start Work on a scalable, high-performance system with a strong focus on clean architecture Gain hands-on experience with cloud technologies and containerization Project This project will focus on developing scalable backend solutions for high-demand business operations, integrating cloud services, and ensuring system reliability. You will work in an agile environment with a strong emphasis on code quality, clean architecture, and performance optimization. Expected competences and knowledge Min. 8 years of experience and proficiency in Java and backend development principles Solid understanding of PostgreSQL and database optimization techniques Hands-on experience with Hibernate Criteria API for efficient data queries Experience with Docker for containerization and deployment In-depth knowledge of the Spring ecosystem ( Spring Boot, Spring Batch) Experience in batch processing using Spring Batch Practical knowledge of AWS services , including ECS, S3, and RDS Openness to adopting and working with AI tools What you'll be doing Developing new application modules based on business requirements Reviewing and improving code , ensuring high maintainability and scalability Designing and implementing efficient backend solutions Writing clean, structured, and scalable code following best practices Technologies you'll work with Java Spring (Boot, Batch) Hibernate REST API PostgreSQL AWS (ECS, S3, RDS) Docker AI Client – why choose this particular client from the Jit portfolio? We have partnered with our Client, a leading HR company with over 60 years of experience and a presence in multiple countries around the world. Our Client provides a wide range of recruitment and job placement services and is dedicated to helping individuals achieve their career goals. In Poland, our Client has been operating for over 20 years and is at the forefront of digitization in the HR services industry. Our team has been building the Time tracking system for our Client since 2019 , a complex tool for registering and settling the working time of full-time and temporary employees working under different legal and organizational conditions, supporting on-boarding processes, and integrating with the employee portal and mobile app. As a member of Jit Team, you will have the opportunity to work on a modern, complex enterprise-class system built in modern technologies such as Java and the AWS cloud . With a business-critical operation, the Work Time system settles working time for tens of thousands of employees every month and contributes to our Client's revenue. 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 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: Long-term B2B role in the banking sector focused on developing and modernizing a global payment platform using Java and React. The position involves building and migrating services to microservices architecture, supporting DevOps practices, and improving automation and processing efficiency in a hybrid work model. 🗂️ Requirements: Strong expertise in Java 17+, Experience with Kubernetes, Knowledge of Git, Proficiency in Unix-based systems and CLI, Experience with SQL and databases, Understanding of RESTful microservices and APIs, Knowledge of HTTP, Experience with JavaScript and React, Experience in DevOps delivery team, Knowledge of Spring or Spring Boot 📃 Skills: Java, React, Kubernetes, Git, Unix, SQL, Oracle, REST, HTTP, JavaScript, Spring, SpringBoot, Microservices, APIs, DevOps 🏢 Description: Project information: Industry: banking Location & Hybrid Model Kraków – 5-6 days per month onsite (Kraków office) Warsaw – 5-6 days per month onsite (Warsaw office) Outside Kraków/Warsaw – 3 days per month from the Warsaw or Kraków office Rate: We’re open to your suggestions Contract : B2B, no end date, long-term cooperation Summary: We are looking for skilled individuals for the payment platform, which allows our customers and clients to move funds across the globe, pay their suppliers, credit salaries, pay taxes directly to authorities and transfer money via multiple channels. The purpose of the role is to support project delivery through high-quality analysis and Agile design artefacts, effective stakeholder management, and deep business insight for the solution delivery team, all enabled by appropriate tools and aligned with DevOps working practices. Responsibilities: Building and supporting services, microservices, and applications (back-end and front-end) in Java 11/17/21, ReactJS, while maintaining and preserving standard products. Reduce costs and complexity by migrating from mainframe and IBM WebSphere to a modern approach with an integration layer such as APIs or microservices patterns. Reduce testing costs by adopting automated testing frameworks. Increasing Straight-Trough-Processing (STP) capabilities of services. Requirements: Strong expertise in Java 17+ is a must Kubernetes & Git knowledge Fluency in navigating Unix-based systems and command-line interfaces is essential. Database technologies and SQL - Oracle preferred (nice-to-have) A working understanding of RESTful microservices and APIs HTTP Web technologies and JavaScript - React Having worked in a DevOps delivery team A desirable understanding of application monitoring. Knowledge of Spring/Spring Boot

🏢 Summary: Senior Java Developer role focused on building secure, scalable enterprise banking applications using modern Java and Spring technologies in a hybrid work model. The position involves developing high-performance REST APIs, managing databases, and supporting CI/CD pipelines within a complex enterprise environment. You will collaborate with cross-functional teams to deliver robust financial solutions. 🗂️ Requirements: 5+ years of Java development experience in enterprise environments, Strong expertise in Java and Spring Boot, Experience with JPA and REST API development, Proficiency with PostgreSQL and Oracle databases, Knowledge of security patterns and testing frameworks, Experience with CI/CD and containerization tools, Communicative proficiency in Polish, Legal right to work in the European Union 📃 Skills: Java, Spring, SpringBoot, JPA, REST, PostgreSQL, Oracle, JUnit, Mockito, OpenShift, Jenkins, GitLab, Maven, Liquibase, Postman, RabbitMQ, Kafka, MongoDB, Camunda, CICD 🏢 Description: Unleash innovation — drive the future of enterprise software development! Wroclaw/Poznań-based opportunity with hybrid work model (up to 4 remote days per week). As a Senior Java Developer , you will be working for our client, a leader in the banking sector dedicated to delivering cutting-edge financial solutions. You will help build robust, secure, and scalable enterprise applications that empower banking institutions and SME clients across Europe. Join us in shaping the digital transformation of financial services and advancing your career in a dynamic, innovative environment. Your main responsibilities: Develop and maintain high-performance Java applications using Spring Boot (preferably 21/25 versions) and Spring frameworks. Design, implement, and optimize REST APIs with security best practices. Collaborate closely with testers, analysts, and Product Owners to deliver seamless solutions. Manage databases including PostgreSQL, Oracle, and utilize JPA for persistence layer development. Use architectural tools such as Postman, Liquibase, Jenkins, Gitlab, Maven, and OpenShift to ensure continuous integration and delivery. Contribute to system security design, integrating technologies like Mockito, JUnit, RabbitMQ, Kafka, and MongoDB. Participate in code reviews, architectural discussions, and testing for quality assurance. Support deployment pipelines and collaborate with cross-functional teams to deliver excellence. You're ideal for this role if you have: 5+ years of experience in Java development within enterprise environments. Strong expertise in Java, Spring (preferably 21/25), JPA, and REST API development. Proficiency in database management, including PostgreSQL and Oracle. Solid knowledge of security patterns and testing frameworks such as JUnit and Mockito. Experience working with containerization and CI/CD tools like OpenShift, Jenkins, and Gitlab. Comfortable working in a collaborative environment with testers, analysts, and Product Owners. It is a strong plus if you have: (optional) Experience with RabbitMQ, Kafka, or MongoDB. Familiarity with Camunda BPM and banking industry solutions. Certifications or knowledge related to these technologies. Language Required for the role: Communicative proficiency in Polish. Eligibility for the role: Only candidates with an existing legal right to work in the European Union will be considered for this role. #MAKEYourCareerBETTER Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data. We offer you At ITDS , you will work on innovative and impactful technology projects for international companies across multiple industries in Europe and beyond. We create an environment for ambitious, driven professionals who want to grow, deliver value, and build their careers in modern IT and digital transformation. Our offer includes: Stable and long-term cooperation with attractive conditions Opportunities to develop your technical expertise across various industries and technologies The chance to work on high-impact, strategic IT and digital transformation projects A clear career path and the opportunity to grow quickly by contributing to diverse client initiatives over time International environment , knowledge sharing, social events, and training opportunities Access to an attractive medical package Access to the Multisport program Access to learning platforms such as Pluralsight Flexible working hours and remote work options Internal number #8702

🏢 Summary: B2B Java Backend Developer role in a greenfield fintech project focused on building a large-scale, event-driven banking platform from scratch. The position involves designing and developing backend services and APIs using Spring within a microservices architecture. You will shape core architecture decisions while working in a cross-functional, international team. 🗂️ Requirements: Minimum 3 years commercial experience in Java backend development, Hands-on experience with Spring Boot, Spring MVC or Spring Cloud, Experience with event-driven architecture and asynchronous processing, Experience with relational databases and PostgreSQL, Ability to design database schemas and write SQL queries, Fluent English (spoken and written) 📃 Skills: Java, Spring, SpringBoot, SpringMVC, SpringCloud, PostgreSQL, SQL, Microservices, EventDriven, Kafka, GCP, Kubernetes 🏢 Description: Salary: 600-900 PLN/MD on B2B Work model: hybrid from Gdynia / Gdańsk / Warszawa / Rzeszów / Kraków (3 days per week from the office) Why choose this offer? Opportunity to build a fintech platform from scratch (greenfield project) Real impact on architecture and core backend services from day one Work in an event-driven, microservices-oriented environment Collaboration within a cross-functional, international team Work on a large-scale financial platform in the banking domain Project We are building a fintech platform from the ground up for a financial institution operating in the banking products space . As a Java Developer, you will be part of a cross-functional squad responsible for designing, developing, and delivering backend services for this greenfield product. You will work closely with your Tech Lead, Senior Developer, Business Analyst, and QA Engineer within a mixed frontend-backend squad. This is a unique opportunity to shape the architecture and codebase of a large-scale financial platform from day one, working in an event-driven, microservices-oriented environment. Responsibilities you'll have: Design, develop, and maintain backend services and APIs for the fintech platform in greenfield project Implement business logic in Java using the Spring framework within an event-driven architecture Work with Postgres databases - design schemas, write queries, and ensure data integrity Collaborate within a cross-functional squad (Tech Lead, Senior Developer, BA, QA, Frontend Developers) to deliver product increments Participate in code reviews, technical discussions, and architectural decisions within the squad Write clean, testable, and well-documented code following team standards and best practices Contribute to continuous improvement of development processes and tooling Communicate progress, blockers, and technical decisions in English to team members and stakeholders Expected competences and knowledge: Min. 3 years of commercial experience in Java backend development (mid-level proficiency expected) Hands-on experience with the Spring framework (Spring Boot, Spring MVC, or Spring Cloud) Experience with event-driven architecture (message brokers, asynchronous processing, event sourcing or similar patterns) Working knowledge of Postgres or comparable relational databases (schema design, SQL, migrations) Fluent English - the ability to communicate freely in a professional setting (spoken and written) Nice to have: Experience with Kafka or similar distributed messaging/streaming platforms Familiarity with Google Cloud Platform (GCP) services Experience with Kubernetes (K8s) and containerized deployments Prior experience working in the financial services or banking domain Experience building systems from scratch (greenfield projects) Technologies you'll work with Java Spring (Spring Boot, Spring MVC, Spring Cloud) PostgreSQL Event-driven architecture Nice to have: Kafka GCP Kubernetes Client – why choose this particular client from the Jit portfolio? The client is a fintech institution operating in the Kingdom of Saudi Arabia, focused on modernising its digital capabilities and expanding its offering for micro-SME customers. It is an organisation with a strong market presence and a clear strategic commitment to innovation, aiming to deliver banking experiences that are fully digital, user-friendly, and deeply integrated with day-to-day business needs. 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 700 experienced experts . We create highly specialised teams for clients from all over the world. We offer team members developmental projects, a wide range of benefits and a proprietary professional development programme. Behind our maxim are also charitable and educational activities. We support pupils and students by donating learning equipment. We offer internships to help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We are a Polish company and we share what we have achieved over 15 years of activity . By supporting indigenous initiatives, we ensure the circulation of good energy.

🏢 Summary: Full Stack Developer role in the automotive industry focused on building and maintaining web applications using modern Java and JavaScript technologies. The project involves developing Angular-based frontends and Spring Boot backends deployed on AWS, with long-term remote collaboration. Full-time B2B engagement with English-speaking client and regular team interactions. 🗂️ Requirements: 5+ years of software development experience, Proficiency in Java, Proficiency in JavaScript, Proficiency in TypeScript, Experience with Spring Boot (Boot, Data, Security), Experience with Angular, Experience with HTML/CSS, Experience with SQL databases, Experience with NoSQL databases, Experience with Hibernate or JPA, Experience with AWS (ECS, EKS, Lambda, CloudWatch), Ability to write unit tests using JUnit 📃 Skills: Java, JavaScript, TypeScript, Angular, HTML, CSS, Spring, SpringBoot, Hibernate, JPA, SQL, NoSQL, AWS, ECS, EKS, Lambda, CloudWatch, JUnit 🏢 Description: 🌍 Remote work: remote (occasional meetings in the Warsaw office; may happen every 2 weeks, with client workshops every 3 months). 💰 Rate: B2B – up to 145 zl/h. 📕 Project language: English. ⏳ Project length: > 12 months + prolongations. ⏰ Start: ASAP / 2 weeks. 💻 Equipment : work on own equipment. 💬 Workload: full time, fixed-price contract : including 30 paid days off (approx. 18.5 working days/month). ⚙️ Recruitment process : 1 interview with the client. 💼 Industry : Automotive. Summary: This role focuses on developing and maintaining robust full stack applications for the PAAK team, primarily using a range of modern web technologies and frameworks . Main Responsibilities: Develop and maintain full stack applications using Java, JavaScript, and TypeScript . Implement web front-ends using Angular and HTML/CSS . Design and manage back-end services with Spring Boot , including integration with databases. Utilize AWS cloud services for deployment and monitoring. Write unit tests and maintain code quality using JUnit. Participate in regular team meetings and client interactions . Key Requirements: 5+ years of experience in software development. Proficiency in Java and JavaScript/TypeScript. Experience with Spring Boot and its ecosystem (Boot, Data, Security). Familiarity with both SQL and NoSQL databases using Hibernate or JPA . Experience using AWS services (ECS/EKS, Lambda, CloudWatch). Nice to Have: Knowledge of CI/CD practices, especially using GitHub Actions . Familiarity with design patterns such as Saga . Experience with container orchestration tools. Other Details: Location: Warsaw Work Schedule: Full time with a specification of 18.5 days work on service order requiring holidays during assignment. Team Interaction: Consultants’ teams meet every 2 weeks; client visits every 3 months. Remote Work: BYOD policy, no travel required.

🏢 Summary: The offer is for a Java Developer responsible for designing, implementing, and upgrading IT systems based on analytical and technical documentation in a hybrid work model. The role involves working with legacy code, performing reverse engineering, integrating distributed systems, and building automated tests. It requires strong experience with Java enterprise technologies and system integration in complex environments. 🗂️ Requirements: Very good knowledge of Java 8+, Strong object-oriented programming skills, Experience in independent design and implementation of application components, Experience in documenting and testing application components, Practical knowledge of Spring and Spring Boot, Practical knowledge of Hibernate and JPA, Knowledge of JEE, Experience with message queue systems, especially RabbitMQ, Experience with Maven, Git, GitLab, Jenkins, Nexus, Jira, Knowledge of relational databases, especially Oracle, Practical knowledge of RESTful API design, Experience in system integration, Experience with distributed systems, Experience with JBoss or WildFly, Knowledge of Fortify and Sonatype, English proficiency at B2 level 📃 Skills: Java, Spring, SpringBoot, Hibernate, JPA, JEE, RabbitMQ, Maven, Git, GitLab, Jenkins, Nexus, Jira, Oracle, REST, JBoss, WildFly, Fortify, Sonatype 🏢 Description: On-site work from Warsaw (5 days per week from the Client's office) Full availability in the Polish time zone Polish language is required English: at least B2 Tasks Design and implementation of IT solutions based on analytical and technical documentation Review and improvement of analytical documentation Creation and maintenance of technical documentation Technical upgrades and modernization of an existing system (including migration to Java 17 and newer technologies like Spring Boot) Work with legacy code and monolithic architecture (Java 8-based system) Reverse engineering based on: existing source code functional and technical documentation documented business processes system UI and database access Participation in transformation of a monolithic TMS system (POS terminal management) towards microservices architecture Defining, designing and implementing automated test cases (including regression testing) Identification of areas for test automation based on code and documentation Work with system security improvements and vulnerability mitigation Close cooperation with operational and development teams (~50% analytical work / ~50% development) Working in Scrum (2-week sprints) in a small development team Supporting system evolution and rollout to new markets (e.g. Germany) Requirements Very good knowledge of Java (8+) and object-oriented programming (experience with Java 17 is a plus) At least 5+ years of experience (Regular/Senior level) Experience in independent design, implementation, documentation and testing of application components Strong analytical skills and ability to work with legacy systems Very good practical knowledge of: Spring / Spring Boot Hibernate / JPA JEE RESTful API design Relational databases (especially Oracle ) Practical experience with: Message queues (RabbitMQ) System integration and distributed systems Application servers (JBoss / WildFly) Development tools: Maven, Git, GitLab, GitLab CI/CD, Jenkins, Nexus, Jira Docker Nice to have: Experience with Linux environments Knowledge of code scanning tools (Fortify, Sonatype) Experience with AI-supported development tools (Codex) Offer Multisport card Private healthcare Access to an e-learning platform Group life insurance