Integration Software Engineer (Java/Kotlin)

🏢 Summary: Senior .NET Developer role focused on designing and maintaining scalable backend services and microservice-based solutions for a European energy trading platform. The position involves building high-performance APIs, integrating messaging systems, and contributing to CI/CD automation in a hybrid work model. The offer includes collaboration with experienced specialists and work with modern technologies. 🗂️ Requirements: 10+ years experience with C# and .NET, Strong experience with SQL databases, Experience with microservices architecture, Experience with messaging systems (RabbitMQ or Kafka), Experience with CI/CD tools (GitHub, GitHub Actions, Octopus Deploy or similar), Ability to design and maintain backend services and APIs, Experience in performance optimization and troubleshooting 📃 Skills: C#, .NET, SQL, RabbitMQ, Kafka, GitHub, GitHubActions, OctopusDeploy, Azure, Angular, Kubernetes, Orleans, CI/CD, Microservices 🏢 Description: Salary: 1000 - 1300 PLN/MD on B2B Work model: elastic hybrid from Gdańsk / Warsaw / Kraków / Rzeszów (1 day from the office a week) Why choose this offer? Working for a leading European energy exchange Collaboration with a team of specialists to create innovative solutions using the latest technologies You can expect a flexible work organization The Jit community will bring you a nice time during regular integration meetings Project We're seeking a Senior .NET Developer who will join our client. Responsibilities you'll have Design, develop, and maintain backend services and APIs using C# and .NET Build and enhance scalable microservice-based solutions Develop and optimize SQL database integrations and data processing workflows Implement and maintain messaging solutions using RabbitMQ, Kafka, or similar technologies Contribute to CI/CD pipelines and deployment automation Collaborate with cross-functional teams to deliver high-quality software solutions Participate in code reviews , architecture discussions, and technical decision-making Monitor, troubleshoot, and improve application performance , scalability, and reliability Expected competences and knowledge Experienced C# .NET developer (ideally 10+ yrs), with experience of SQL databases Experience with microservices and messaging infra (RabbitMQ & Kafka or similar) Experience in CI/CD tools such as GitHub, GitHub Actions, Octopus Deploy or similar What we consider a plus Fintech experience Frontend experience (Angular or similar) Experience using Microsoft Azure platform and infrastructure services Some prior experience or knowledge about containerization and container orchestration (Kubernetes) Experience of implementing high-load and scalable applications using the Actor Model (Orleans) Technologies you'll work with C# .NET SQL Azure Messaging solutions CI/CD tools Angular Kubernetes Client – why choose this particular client from the Jit portfolio? Our client is the leading European power market company which delivers efficient, simple, and secure trading across Europe . In 2023 they celebrate 30 years of powering the market. The company offers day-ahead and intraday trading, clearing and settlement, and additional services to customers, regardless of size or location. Currently, 360 traders from 20 countries operate on their markets. The company provides services on markets in the Nordic and Baltic regions, Germany, Poland, France, the Netherlands, Belgium, Austria, Luxembourg, and the UK. Our client is a Nominated Electricity Market Operator (NEMO) in 15 European countries, while also servicing power markets in Bulgaria, Croatia, and Georgia . In 2021 they had a total traded power turnover of 963 TWh. Our client has three decades of power market experience built on offering flexibility, transparency, innovation, greater choice, and opportunities on the electricity market. 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: Full Stack Developer role focused on building and modernizing a cloud-based SaaS platform in Microsoft Azure for managing and optimizing district heating and energy systems. The position involves end-to-end development across Node.js backend services and React frontend applications, working with real-time data, integrations, and distributed cloud environments. The offer includes ownership of features from development to production in a quality-driven, Agile team. 🗂️ Requirements: Minimum 3 years commercial experience as Full Stack Developer, Strong experience with Node.js and TypeScript, Strong experience with React and TypeScript, Experience building and maintaining REST APIs, Experience with MySQL and MongoDB, Experience with InfluxDB, Experience with automated unit and integration testing, Experience with Git and pull request workflows, Ability to work within large existing codebases, Understanding of safe data operations and data integrity, Experience working in Agile/Scrum environments, Good written and spoken English 📃 Skills: Node.js, TypeScript, React, REST, MySQL, MongoDB, InfluxDB, MQTT, Docker, Kubernetes, Azure, AzureDevOps, CI/CD, YAML, Grafana, Sentry, Cypress, Git, pnpm 🏢 Description: Salary: 700 - 850 PLN/MD on B2B Work model: hybrid from Gdańsk / Warszawa / Kraków / Rzeszów Why choose this offer? Work on a modern SaaS platform hosted in the cloud (including Microsoft Azure), used to manage and optimize district heating and energy systems Join a distributed team working across the full technology stack, from backend services to frontend applications Take ownership of features from development through production deployment Work in an environment that values automated testing, code quality, and peer code reviews Contribute to a platform with a real-world impact on energy efficiency and operational optimization Project The project is a cloud-based SaaS platform hosted in Microsoft Azure that supports the management and optimization of district heating networks, heating substations, and other components of heating infrastructure. The application collects and processes data from meters, sensors, network measurements, and controllers, enabling remote monitoring, configuration, and control of connected devices. It provides real-time and historical analysis of energy consumption and operational parameters , along with reporting, alerting, dashboards, maps, and data visualizations that help operators efficiently oversee entire heating networks. The platform also integrates with external data sources, such as weather forecasts and optimization systems, to improve operational efficiency and decision-making. The successful candidate will initially focus on modernizing and improving internal tools before moving into feature development and platform-related initiatives. The role involves broad full-stack development across Node.js backend services and React-based frontend applications, working within a large, established codebase and contributing to solutions used in a distributed, cloud-native environment. Expected competences and knowledge Minimum 3 years of commercial experience as a Full Stack Developer working with Node.js, TypeScript and React Strong experience with Node.js and TypeScrip t for building and maintaining backend services and REST APIs Strong experience with React and TypeScript , including modern hooks-based development and component design Experience working with MySQL, MongoDB, and ideally InfluxDB , with a solid understanding of data modelling, querying, performance optimization, and maintaining data integrity across relational and document databases Ability to work effectively within a large existing codebase, following established patterns and safely extending applications and services built by other engineers Practical experience with automated testing , including unit and integration testing as a standard part of the development process Experience working with Git and pull request-based workflows , including participating in code reviews and providing constructive feedback Understanding of safe and reliable data operations , including idempotency, handling partial failures, and minimizing risks associated with data modifications Good written and spoken English skills , enabling effective collaboration within a distributed, international team Experience working in Agile/Scrum environments , including estimation, stand-ups, sprint planning, and sprint commitments Proactive, self-organized approach to work , with the ability to identify and communicate blockers early Strong ownership mindset and accountability for delivering features from development through production Nice to have: Experience with microservices and event-driven architectures, including message brokers, queues, and pub/sub patterns Familiarity with MQTT and systems processing telemetry or IoT device data Experience with Docker and basic knowledge of Kubernetes Experience working in monorepo environments and with pnpm workflows Familiarity with Microsoft Azure and Azure DevOps CI/CD pipelines Understanding of observability concepts, including logs, metrics, and traces, with tools such as Grafana and Sentry Experience with Cypress or other end-to-end testing frameworks Experience with event sourcing architectures Knowledge of IoT, industrial protocols, or domains such as energy management, district heating, building management systems, or smart infrastructure solutions Technologies you'll work with Node.js TypeScript React REST APIs MySQL MongoDB InfluxDB MQTT Job Queues Docker Kubernetes pnpm Monorepo Architecture Microsoft Azure Azure DevOps CI/CD Pipelines (YAML) Grafana Sentry Cypress Git Automated Testing (Unit, Integration, E2E) Client – why choose this particular client from the Jit portfolio? Our Client engineers technologies that enable the world of tomorrow to do more with less. They meet the growing need for infrastructure, food supply, energy efficiency and climate-friendly solutions . Their products and services are used in areas such as refrigeration, air conditioning, heating, motor control and mobile machinery. They are also active in the field of renewable energy as well as district heating infrastructure for cities and urban communities. Their innovative engineering dates back to 1933 and today our Client is a world-leader , employing more than 27,000 employees and serving customers in more than 100 countries . They are still privately held by the founding family. 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: Junior-level role in a project building a high-performance, scalable messaging platform for financial institutions, focused on message transport, transformation, routing, and monitoring in a critical environment. The position offers hands-on experience with enterprise financial systems and development toward Java backend or DevOps paths. Work is in a hybrid model with on-call support in a time-sensitive setup. 🗂️ Requirements: Basic experience in Java, Interest in DevOps, Good command of English (spoken and written), Availability for on-call support (rotational shifts), Ability to work in time-sensitive environments, Problem-solving skills, Willingness to work on-site 2 days per week 📃 Skills: Java, Spring, SpringBoot, Kubernetes, OpenShift, Docker, ActiveMQ, IBMMQ, Elasticsearch, PostgreSQL, DB2, ArgoCD, GitOps, Incentage 🏢 Description: Salary: 252 - 350 PLN/ day net + vat (B2B/Civil contract) Remote: elastic hybrid from our office in Gdynia/Gdańsk (2 days per week on-site) Why choose this offer? International working environment High level of autonomy and collaboration within the team Scandinavian organizational culture supporting real work-life balance Opportunity to learn how financial products and markets operate Project You’ll join a project focused on building a robust, scalable, high-performance messaging platform for financial institutions. The system handles message transport, data transformation, routing, validation, sequencing, and monitoring. It’s a critical, high-throughput environment where reliability matters and attention to detail makes a real impact. Expected competences and knowledge Junior level with strong learning mindset): Basic experience in Java (commercial or solid personal projects) Interest in DevOps, with an eagerness to learn Good command of spoken and written English Problem-solving mindset and ability to react quickly to issues Responsibility and readiness to work in time-sensitive environments Openness to collaboration and knowledge sharing (tech + business teams) Availability for on-call support (morning/evening shifts on rotation) Nice to have: Spring Boot Kubernetes / OpenShift Docker Messaging systems (Apache ActiveMQ, IBM MQ) Elasticsearch Databases (PostgreSQL, DB2) GitOps (ArgoCD) Experience with low-code platforms (e.g., Incentage IMS) What you gain: Exposure to real-world, large-scale financial systems Fast learning curve in a complex enterprise environment Supportive team that helps you grow (no “figure it out alone” culture) Development path toward Java backend / DevOps / Site Reliability Engineer Technologies you'll work with Spring Boot Kubernetes / OpenShift Docker Messaging systems (Apache ActiveMQ, IBM MQ) Elasticsearch Databases (PostgreSQL, DB2) GitOps (ArgoCD) Low-code platforms (e.g., Incentage IMS) Client – why choose this particular client from the Jit portfolio? Jit Team is proud to partner with one of the leading European financial groups responsible for the registration, ownership records, and financial settlement of securities traded on financial markets in Norway and recently extended to other European markets. Jit Team has been a strategic partner to our client in the area of software development since 2017 . Over the course of the partnership, Jit Team's dedicated team working for our client has grown from three to over 30 people , who have worked on the modernization of legacy applications, the implementation of new systems, and the development of a private cloud-based platform to host a variety of financial systems . 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: Tech Lead role in a Java team responsible for designing, developing, and maintaining scalable, secure software solutions in a Scrum environment. The position combines hands-on Java development with technical leadership, focusing on architecture, microservices, and cloud-based systems on AWS. You will translate business requirements into robust technical solutions aligned with architectural and non-functional standards. 🗂️ Requirements: Strong commercial experience in Java development, Hands-on experience with Spring Boot in production, Experience with AWS in production environments, Experience designing microservices and distributed systems, Strong knowledge of software architecture and design patterns, Experience addressing non-functional requirements (scalability, security, performance), Experience with Docker and CI/CD pipelines, Experience building and maintaining REST APIs 📃 Skills: Java, SpringBoot, AWS, EC2, RDS, S3, CloudWatch, Microservices, Docker, CI/CD, REST, Security, Architecture, DesignPatterns, DistributedSystems 🏢 Description: Salary: 1300 - 1600 PLN/MD on B2B Work model: e lastic hybrid (Warsaw / Kraków / Tricity) or remote with occasional office visits Why choose this offer? You can expect a flexible work organization The international work environment will allow you to interact with the English language daily Scandinavian organizational culture will provide you with a work-life balance The Jit community will bring you a nice time during regular integration meetings Project We are looking for an experienced Tech Lead to join a Java development team responsible for designing, developing, and maintaining high-quality software solutions. This role combines hands-on engineering with technical leadership , focusing on building scalable, secure, and maintainable systems while mentoring the team and driving technical excellence. As a Tech Lead , you will play a key role in t ranslating business requirements into robust technical solutions , ensuring alignment with architectural standards , non-functional requirements (NFRs) , and the broader technology strategy . You will work in an autonomous, self-organizing Scrum team and actively contribute to both delivery and continuous improvement. Expected competencies and knowledge Strong hands-on experience as a Senior Software Engineer with a primary focus on Java development Ability to combine active coding with technical leadership and ownership of technical decisions within the team Proven experience in designing and delivering secure, scalable, and high-quality software solutions Extensive experience with Spring Boot and AWS in production environments Strong understanding of software architecture, design patterns, and non-functional requirements (scalability, security, performance) Experience in designing and working with microservices and distributed systems Ability to coach developers, promote best practices, and support a self-organizing Scrum team Experience working closely with Product Owners and cross-functional stakeholders to translate business requirements into technical solutions Very good communication skills and fluency in spoken and written English Technologies you'll work with Java Spring Boot (REST APIs, Security, Data) AWS (EC2, RDS, S3, CloudWatch) Microservices architecture Docker & CI/CD Nice to have: Kafka React Basic knowledge of C# Client – why choose this particular client from the Jit portfolio? Our client is a Scandinavian supplier of software and services for purchasing and tendering processes in highly formalized conditions, such as orders in accordance with public procurement law at the level of the European Union or individual member states. The delivery center is located in Utrecht. Client’s platforms allow to announce tenders and conduct the entire procedure of collecting and evaluating offers at every stage of the purchasing process. They are used both by public administration bodies at various levels in European countries and by purchasing departments of large companies and corporations. 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: B2B role for an experienced Java Developer to design and develop high-availability, horizontally scalable microservices supporting an advertising and billing platform. The position involves working on production systems with real impact on architecture, distributed communication, and system performance. Collaboration with cross-functional teams and Polish-speaking stakeholders is required. 🗂️ Requirements: Minimum 4 years commercial experience as Java Developer, Hands-on experience in production environments, Higher education in relevant field (completed or in progress), Professional proficiency in Polish (spoken and written), Strong knowledge of Java 11+, Practical experience with Spring Boot, Experience with microservices architecture in production, Experience with Kafka or RabbitMQ, Understanding of distributed systems, Advanced knowledge of SQL without ORM usage, Experience with monitoring, logging and metrics, Understanding of asynchronous communication, Familiarity with reactive programming 📃 Skills: Java, Spring, SpringBoot, SQL, NoSQL, Kafka, RabbitMQ, WebFlux, Reactor, Microservices, Kotlin, Hibernate, JPA, Monitoring, Logging 🏢 Description: Salary: 750 - 1000 PLN/MD on B2B Work model: elastic hybrid from Gdynia/Warszawa/Rzeszów/Kraków Why choose this offer? Real impact on system architecture Opportunity to design solutions with high availability and horizontal scalability Collaboration within a mature, cross-functional team Direct communication with Product Owners and non-technical stakeholders Project The team is directly involved in managing advertising campaigns. This enables sellers and advertising agencies to create ads, which are then delivered for airing on the company's portal (e.g., sponsored listings, homepage) and on other platforms such as Google. Additionally, the team is responsible for budgeting and advertising billing. They collaborate closely with teams handling the airing of various types of ads, frontend development, and offers visible on the portal. The project is conducted primarily in Polish, therefore professional working proficiency in Polish (spoken and written) is required. Expected competences and knowledge Minimum 4 years of commercial experience as a Java Developer, with mandatory hands-on experience in production environments Required higher education in a relevant field (or currently in progress) Fluent or professional working proficiency in Polish (spoken and written) Good knowledge of Java 11+ (Kotlin is a plus) First hands-on experience with Spring Boot Practical experience with microservices architecture in production environments Familiarity with messaging systems such as Kafka or RabbitMQ Basic understanding of distributed systems and asynchronous communication Solid understanding of relational databases ( SQL ), including indexes, constraints, and transactions (without relying on ORM frameworks such as Hibernate/JPA) Experience working with monitoring, logging, and application metrics Ability to work in a cross-functional team environment Familiarity with reactive programming concepts Technologies you'll work with Java 11+ Spring Boot NoSQL databases Spring WebFlux / Project Reactor Relational databases (advanced SQL) Nice to have: Kafka Kotlin Event-driven architecture Client – why choose this particular client from the Jit portfolio? Our Client dominates the Polish e-commerce arena as the market leader since 1999 . With a user base of over 20 million and growing, this well-established platform is at the forefront of e-commerce, constantly striving for growth through market expansion and investment. As a major player in technology, our Client boasts a talented IT team of over 1,000 employees who focus on developing their own cutting-edge technologies. Jit Team has had a successful partnership with our Client since spring 2021 , with multiple software development teams dedicated to our Client's platforms. These teams operate autonomously, designing platform components through micro-services. Working with our Client offers a chance to contribute to a solution used by millions on a daily basis and to tackle the challenge of delivering software at a massive scale , where even a single second of delay can have a significant impact. This project provides a unique opportunity to work with state-of-the-art technologies and tools, making it a rare and valuable experience. 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: B2B contract for an experienced Java Developer in the energy sector (100% remote, July–December 2026) focused on adapting existing BAM services (Opera, STO3) and implementing integration solutions to replace the current Exchange Tool. The role centers on designing and delivering technical integrations, interfaces, and deployment plans within a complex system landscape. 🗂️ Requirements: 4+ years of experience in Java development, Proven experience with Java, Experience with SpringBoot, Experience with Kotlin, Experience with JavaScript and TypeScript, Experience with Angular, Experience with Docker and Kubernetes, Experience with Kafka, Experience with Postgres, Experience with RichClients, Ability to design and implement technical integration concepts, Experience in creating interfaces and adapters, Experience in testing and technical documentation, Experience in designing cutover and rollback plans, Relevant degree in ComputerScience or equivalent 📃 Skills: Java, SpringBoot, Kotlin, JavaScript, TypeScript, Angular, Docker, Kubernetes, Kafka, Postgres, RichClients, PowerBid, BAM, Opera, STO3 🏢 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: 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: 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: Full Stack Developer role in the payment domain focused on building and scaling high-performance, distributed financial applications using Java and Angular. The position involves developing robust backend services, REST APIs, and modern frontend solutions, with strong emphasis on reactive programming, automated testing, and CI/CD practices. The project operates in an international environment with hybrid work model. 🗂️ Requirements: Minimum 5 years of experience as Full Stack Developer, Strong experience with Java, Strong experience with Spring Boot, Experience with reactive programming (e.g. RxJava), Solid knowledge of Angular or AngularJS, Experience with TypeScript, Experience in REST API development, Hands-on experience with unit testing, Experience with test automation frameworks (e.g. Cucumber), Experience with build tools and CI/CD pipelines 📃 Skills: Java, SpringBoot, Angular, AngularJS, TypeScript, RxJava, REST, Cucumber, CI/CD, UnitTesting, ReactiveProgramming 🏢 Description: Salary: 1000 - 1300 PLN/day on B2B Work model: hybrid from Gdynia / Gdańsk / Warszawa / Łódź (3 days per week from the office) Why choose this offer? You can expect a flexible work organization The international work environment will give you the opportunity to interact with the English language on a daily basis Scandinavian organizational culture will provide you with work-life balance, you will gain time for additional training (financed by Jit) The Jit community will bring you a nice time during regular integration meetings Project You will be involved in a dynamic project within the payment domain, focused on building and scaling modern, high-performance financial applications. The team works on developing robust, distributed systems with an emphasis on reliability, scalability, and seamless user experience. Responsibilities you'll have Design, develop, and maintain full stack applications using Java and Angular Build and enhance backend services using Spring Boot and reactive programming (e.g. RxJava) Create and maintain RESTful APIs for seamless system integration Actively participate in application testing to prevent QA bottlenecks during high delivery periods Contribute to automated testing using unit tests and frameworks such as Cucumber Collaborate closely with cross-functional teams to improve performance and delivery flow Work with build tools and CI/CD pipelines to streamline development processes Expected competences and knowledge Minimum 5 years of experience as a Full Stack Developer Strong experience with Java and Spring Boot Experience with reactive programming approaches and libraries (e.g. RxJava) Solid knowledge of Angular/AngularJS and TypeScript Experience in REST API development Hands-on experience with unit testing and test automation Familiarity with automation frameworks (e.g. Cucumber) Strong problem-solving skills and engineering mindset Excellent communication skills and ability to work in a team Experience in the payment domain is a plus Technologies you'll work with Java, Spring Boot Angular / AngularJS, TypeScript RxJava (or similar reactive libraries) REST APIs Cucumber and test automation tools Build tools and CI/CD solutions Client – why choose this particular client from the Jit portfolio? Jit Team has had an over-decade-long relationship with the leading financial group in the Nordic countries, and we are privileged to be our client's premier partner in Poland. At present, over 200 Jit personnel are engaged in the completion of more than 60 projects for this Norwegian major provider of financial services with a global presence and a strong focus on modern technology. Our customer's work atmosphere is epitomized by the Scandinavian culture , which is conducive to people who place emphasis on work-life balance and feedback culture . Furthermore, all projects are executed in international teams, giving constant exposure to the English language. 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: B2B Java Developer role in a financial project modernizing and rebuilding a digital banking channel for corporate clients. The position involves developing and enhancing APIs, contributing to system modernization from legacy platforms, and working across microservice and monolith architectures in a SAFe Agile environment. The project focuses on resilient, domain-driven solutions supporting core banking services such as payments and accounts. 🗂️ Requirements: Minimum 6 years of experience in Java development, Experience in building API solutions, Experience with Spring and Hibernate, Experience with SQL and REST, Experience with Microservices architecture, Minimum 2 years of experience with Angular, Experience with Cucumber, Experience with Jasmine unit testing, Knowledge of SOLID principles, Knowledge of design patterns, Experience with GIT, Experience working in Agile environment, Familiarity with reactive programming, Knowledge of Domain Driven Design (DDD) 📃 Skills: Java, Spring, Hibernate, Angular, SQL, REST, Microservices, GIT, Cucumber, Jasmine, Reactive, DDD, SAFe 🏢 Description: Salary: 1000 - 1200 PLN/day on B2B Work model: elastic hybrid from Gdynia / Gdańsk / Warszawa (3 days per week from the modern office) Why choose this offer? You can expect a flexible work organization The international work environment will give you the opportunity to interact with the English language on a daily basis Scandinavian organizational culture will provide you with work-life balance, you will gain time for additional training (financed by Jit) The Jit community will bring you a nice time during regular integration meetings Project You will be involved in a financial project focused on modernising and building a new digital banking channel for corporate customers. The initiative aims to replace the legacy platform and redefine how clients manage payments, accounts, liquidity, and user permissions. The team operates within the SAFe Agile framework, delivering resilient solutions across microservice and monolith architecture using DDD and port-adapter approach. Responsibilities you'll have Developing new features that modernise the platform and support maintenance and compliance requirements Building and enhancing API solutions to support essential banking services such as Accounts, Payments, File Transfer, and international and local services Contributing to system modernisation and transition from legacy solutions Working within microservice and monolith architecture Collaborating closely with developers, Product Owner, architects, analysts and QA Participating in Agile (SAFe) ceremonies and delivering high-quality software in an international environment Expected competences and knowledge Hands-on experience in Java development (preferred at least 6 years) Experience in building API solutions Familiarity with reactive programming Working knowledge of Spring, Hibernate and Cucumber Experience with SQL, REST, Microservices and GIT 2 years of experience with Angular Working knowledge of unit testing in Jasmine Knowledge of SOLID principles and design patterns Experience working in an Agile environment Technologies you'll work with Java Spring Angular Cucumber Hibernate Jasmine SQL REST Microservices GIT Reactive stack Domain Driven Design (DDD) SAFe Agile framework Client – why choose this particular client from the Jit portfolio? Jit Team has had an over-decade-long relationship with the leading financial group in the Nordic countries, and we are privileged to be our client's premier partner in Poland. At present, over 200 Jit personnel are engaged in the completion of more than 60 projects for this Norwegian major provider of financial services with a global presence and a strong focus on modern technology. Our customer's work atmosphere is epitomized by the Scandinavian culture , which is conducive to people who place emphasis on work-life balance and feedback culture . Furthermore, all projects are executed in international teams, giving constant exposure to the English language. 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.