Regular Kotlin Developer (f/m/x)

🏢 Summary: Role focused on designing and developing scalable microservices for a modern fintech expense management platform integrating payments, cards, and invoicing into partner systems. The position involves leading technical initiatives, optimizing system performance, and ensuring high reliability in a cloud-based distributed environment. You will also mentor engineers and drive technical improvements across the platform. 🗂️ Requirements: Minimum 5 years of professional software development experience, Strong expertise in Kotlin, Experience with distributed systems, Experience with microservices architecture, Experience with cloud environments (AWS, Kubernetes), Proficiency with PostgreSQL or other relational databases, Experience with JUnit and Testcontainers, Experience with observability tools such as Grafana, Very good English (minimum B2), Fluent Polish, Residence in Poland 📃 Skills: Kotlin, AWS, Kubernetes, PostgreSQL, JUnit, Testcontainers, Grafana, Microservices, DistributedSystems, Cloud 🏢 Description: Join a team working on a modern fintech platform that supports company expense management. The project focuses on developing a finance solution that enables seamless integration of financial tools (including payment cards, expense management, and invoice handling) directly into partner systems such as banks, accounting platforms, and HR solutions. The product being developed allows companies to simplify financial processes, automate settlements, and gain full real-time control over their spending. Your tasks Leading initiatives to design, build, and maintain scalable microservices primarily using Kotlin Collaborating with cross-functional teams to develop innovative solutions across Platform, Services, SMB, and other domains Analyzing system performance and implementing optimizations to ensure high reliability and scalability Participating in code reviews, post-mortems, and providing mentorship to other engineers Proactively improving the architecture and quality of solutions, and leading the team through technical challenges and migrations Requirements Minimum 5 years of professional experience in software development Expertise in server-side languages, especially Kotlin, and experience with distributed systems, microservices, and cloud environments (e.g., AWS, Kubernetes) Proficiency with relational databases like PostgreSQL, testing frameworks (e.g., JUnit, Testcontainers), and observability tools like Grafana Strong problem-solving skills and a collaborative mindset to mentor and upskill your teammates Very good knowledge of English - min. B2 level Residing in Poland required Nice-to-have requirements Previous work in the fintech industry or with financial products Knowledge of topics related to payments, cards, or accounting Experience working in a scale-up environment Proficiency in one of the following front-end technologies: React or TypeScript What we offer Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more Comfortable workplace – class A offices or remote work Dozens of fascinating projects for prestigious brands from all over the world PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers Investment in your growth – meetups, webinars, training platform and technology blog – you choose Fantastic atmosphere created by all Sii Power People If you want to work on systems with high operational significance — apply now!

🏢 Summary: Senior Frontend Engineer role focused on building and scaling a modern fintech platform for managing corporate spending. The position involves leading development of React and TypeScript-based SPA applications, integrating with microservices and APIs, and driving performance and architectural improvements. You will collaborate cross-functionally while mentoring engineers and shaping scalable front-end solutions in a cloud-native environment. 🗂️ Requirements: 5+ years professional software engineering experience, Strong commercial experience with React, Strong expertise in TypeScript, Advanced knowledge of modern JavaScript (ES6+), Experience building large-scale SPA applications, Experience designing scalable front-end architectures, Experience working with APIs and microservices-based systems, Hands-on experience with front-end testing (unit, integration, e2e), Experience with CI/CD pipelines, Experience with AWS, Experience with Kubernetes, Professional English proficiency (min. B2), Fluent Polish, Residence in Poland 📃 Skills: React, TypeScript, JavaScript, ES6, SPA, REST, GraphQL, Microservices, CI/CD, AWS, Kubernetes, Testing, SSR 🏢 Description: Join a team building a modern fintech platform that helps businesses manage company spending more efficiently. The project focuses on developing a financial product that enables seamless integration of financial tools—including corporate cards, expense management, and invoice processing—directly with partner ecosystems such as banks, accounting platforms, and HR systems. The platform empowers companies to automate financial operations, simplify reconciliation processes, and gain full real-time visibility into their spending. Your tasks Lead initiatives focused on designing, building, and maintaining scalable front-end applications primarily using React and TypeScript Build modern, performant, and intuitive user interfaces for key areas of the fintech platform Collaborate closely with cross-functional teams across backend engineering, product, and design to deliver scalable product solutions Integrate front-end applications with microservices-based architectures and APIs (REST / GraphQL) Analyze application performance and implement optimizations to ensure high responsiveness, reliability, and scalability Participate in code reviews, architecture discussions, and post-mortems while mentoring other engineers Proactively address technical debt and guide the team through technical challenges, refactoring initiatives, and architectural migrations Requirements At least 5 years of professional software engineering experience, including strong commercial experience with React Strong expertise in TypeScript, modern JavaScript (ES6+), and building large-scale SPA applications Solid experience designing scalable front-end architectures using component-based and modular design principles Experience working with APIs and distributed systems in microservices-based environments Hands-on experience with front-end testing frameworks (unit, integration, e2e) and observability/monitoring tools Previous work with CI/CD pipelines, cloud environments such as AWS, and container orchestration platforms like Kubernetes Strong problem-solving skills, ownership mindset, and passion for mentoring and elevating engineering teams Professional English proficiency - minimum B2 Fluent in Polish required Residing in Poland required Nice-to-have requirements Previous experience in fintech or building financial products Understanding of payments, cards, expense management, or accounting-related domains Experience working in a scale-up environment Experience with GraphQL, SSR, performance optimization, or building design systems What we offer Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more Comfortable workplace – class A offices or remote work Dozens of fascinating projects for prestigious brands from all over the world PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers Investment in your growth – meetups, webinars, training platform and technology blog – you choose Fantastic atmosphere created by all Sii Power People If you want to work on systems with high operational significance — apply now!

🏢 Summary: The role involves designing and developing scalable backend systems in a microservices architecture using Java or Kotlin and Spring. The engineer will influence technical decisions while building payment and subscription platforms with event-driven communication and cloud-based solutions. The position includes working with modern architectural patterns and ensuring high code quality through testing and reviews. 🗂️ Requirements: Strong experience with Java and/or Kotlin, Solid knowledge of Spring and Spring Boot, Hands-on experience with SQL and relational databases, Experience with PostgreSQL, Proven experience with microservices architecture, Experience with event-driven systems, Practical experience with JUnit, Mockito, Testcontainers, Experience with AWS or GCP, Understanding of DDD, CQRS, Hexagonal Architecture, Experience with payment or subscription systems 📃 Skills: Java, Kotlin, Spring, SpringBoot, SQL, PostgreSQL, Microservices, Kafka, JUnit, Mockito, Testcontainers, AWS, GCP, DDD, CQRS, HexagonalArchitecture 🏢 Description: Senior Backend Engineer (Java/Kotlin) We are looking for an experienced Backend Engineer to join a team building modern, scalable systems based on a microservices architecture. This role offers real influence over technical decisions, system architecture, and the quality of delivered solutions—particularly within payment and subscription platforms. Responsibilities Design, develop, and maintain backend systems using Java or Kotlin and the Spring Framework Build and evolve microservices following DDD , CQRS , and Hexagonal Architecture principles Implement event-driven communication , ideally using Apache Kafka Work with relational databases ( PostgreSQL or other SQL databases ) and optimize queries Write unit and integration tests using JUnit, Mockito, and Testcontainers Contribute to the design and development of cloud-based solutions ( AWS or GCP ) Participate in code reviews and drive high engineering standards Collaborate closely with product and engineering teams to deliver business-critical features Requirements Strong experience with Java and/or Kotlin Solid knowledge of Spring / Spring Boot Hands-on experience with SQL and relational databases (preferably PostgreSQL ) Proven background in microservices-based architectures Experience with event-driven systems (Kafka is a strong plus) Practical experience with backend testing (JUnit, Mockito, Testcontainers) Experience working with cloud platforms ( AWS or GCP ) Good understanding of Domain-Driven Design (DDD) , CQRS , and Hexagonal Architecture Must-have: experience with payment systems and/or subscription-based platforms Nice to Have Experience working with high-scale, high-availability systems Knowledge of security and transactional data handling Background in product-driven, Agile environments

🏢 Summary: Mid-Level Kotlin/Java Developer role focused on building and enhancing a microservices-based Developer Experience platform in the fintech domain. The position involves designing and implementing web applications and APIs, improving compliance and automation through scalable cloud-integrated solutions. The role follows a hybrid model in Krakow and emphasizes Agile delivery and high-quality code practices. 🗂️ Requirements: 3+ years experience with Java or Kotlin, Experience in API development, Experience with SQL databases, Knowledge of HTML, Knowledge of JavaScript, Understanding of microservices architecture, Experience working in Agile environments, Experience with Jira and Confluence, Strong troubleshooting skills, English B2+ level, Legal right to work in the EU 📃 Skills: Java, Kotlin, SQL, HTML, JavaScript, Microservices, APIs, Agile, Jira, Confluence, CICD, Jenkins, AWS, Azure, GCP, Linux, AIX, WAS, Testing, TestAutomation 🏢 Description: Unleash innovation through code — drive the next evolution of microservices and cloud integration! Krakow-based opportunity with hybrid work model As a Mid-Level Kotlin/Java Developer , you will be working for our client, a leading player in the financial technology industry, focused on building a cutting-edge Developer Experience platform. You will help develop a robust microservice architecture to enhance compliance and streamline development processes, shaping the future of software control and automation. Join us and be part of a transformative journey that fosters innovation and career growth. Your main responsibilities: Collaborate with cross-functional teams to design, develop, and implement web applications and APIs using Kotlin and Java. Build and maintain microservices that address critical business challenges and improve developer experience. Work closely with testers and other developers to ensure high-quality, efficient code delivery. Proactively engage with customers and internal stakeholders to resolve issues and incorporate feature requests. Participate in Agile practices, including peer reviews, automated testing, and continuous integration/deployment workflows. You're ideal for this role if you have: 3+ years of experience in Java, Kotlin, or related development fields. Strong expertise in API development, databases (SQL), and front-end technologies such as HTML/Javascript. Solid troubleshooting skills and experience working within Agile environments using Jira/Confluence. Good understanding of microservice architecture. Excellent communication skills in English (B2+). It is a strong plus if you have: (optional) Cloud technology experience (AWS, Azure, GCP). Knowledge of CI/CD toolchains like Jenkins. Background in Systems Administration across Linux/AIX/WAS platforms. Test Automation skills. Language Required for the role: English (B2+ level) 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.

🏢 Summary: Long-term B2B contract for a Senior Android Developer to design and implement Android applications in a fintech onboarding domain. The role combines Kotlin/Jetpack Compose mobile development with Java-based microservices and REST integration in a hybrid work model. The position involves architectural guidance and close collaboration with cross-functional teams. 🗂️ Requirements: 5+ years of Android development experience, Proficiency in Kotlin, Experience with Jetpack Compose, Strong knowledge of Android SDK, Hands-on experience with Architecture Components, Experience with OkHttp or similar networking tools, Strong understanding of Java, Experience with Spring framework, Experience with microservices integration, Working knowledge of SQL, Experience with unit testing 📃 Skills: Kotlin, Java, Android, Jetpack, Compose, SDK, Spring, Microservices, REST, SQL, OkHttp, MVVM, Koin, Fintech 🏢 Description: GENERAL INFORMATION: Industry : fintech Location : Warsaw (hybrid work model - 2x month in the office) Rate : up to 165 PLN/h Form of cooperation: B2B Project duration : long-term ROLE SUMMARY : The Android Developer role is focused on facilitating customer onboarding while maintaining the fintech app functionality across diverse markets. MAIN RESPONSIBILITIES: The primary duty of the Android Developer is to design and implement robust Android applications while collaborating across teams. Design and implementation of Android applications using Kotlin and Jetpack Compose. Build and optimize Java backend microservices and REST endpoints. Translate business requirements into technical solutions in collaboration with stakeholders. Act as a technical reference point for team members and guide architectural decisions. Encourage innovation and the adoption of new technologies for operational excellence. Communicate complex technical concepts to non-technical stakeholders effectively. Foster a culture of mentorship and shared learning within the team. Communicate clearly in both Polish and English while adapting language for diverse audiences. KEY REQUIREMENTS: 5+ years of experience in Android development. Proficiency in Kotlin, Google Jetpack Compose, and Android SDK. Hands-on experience with Architecture Components and networking tools such as OkHttp. Strong understanding of Java, Spring and microservices integration. Working knowledge of SQL and experience with unit testing. NICE TO HAVE: Experience in the Fintech industry. Knowledge of Koin DI and MVVM architecture. A proactive mindset and excellent communication skills. OTHER DETAILS: The position is based in Warsaw, within a team structure of 2 developers, 1 tester, a scrum master, a product owner, and business analysts. The work model is hybrid, requiring 2 office days per week, with flexible working hours.

🏢 Summary: Long-term B2B contract for an Android Developer in a fintech project focused on customer onboarding and maintaining mobile app functionality across multiple markets. The role involves building Android applications with Kotlin and Jetpack Compose and contributing to Java-based backend microservices and integrations. The position combines mobile development with backend collaboration in a hybrid work model. 🗂️ Requirements: 5+ years of Android development experience, Proficiency in Kotlin, Experience with Jetpack Compose, Strong knowledge of Android SDK, Hands-on experience with Architecture Components, Experience with OkHttp or similar networking tools, Strong understanding of Java, Experience with Spring framework, Experience with microservices integration, Working knowledge of SQL, Experience with unit testing 📃 Skills: Android, Kotlin, JetpackCompose, AndroidSDK, ArchitectureComponents, OkHttp, Java, Spring, Microservices, SQL, UnitTesting 🏢 Description: GENERAL INFORMATION: Industry : fintech Location : Warsaw (hybrid work model - 2x month in the office) Rate : up to 165 PLN/h Form of cooperation: B2B Project duration : long-term ROLE SUMMARY : The Android Developer role is focused on facilitating customer onboarding while maintaining the fintech app functionality across diverse markets. MAIN RESPONSIBILITIES: The primary duty of the Android Developer is to design and implement robust Android applications while collaborating across teams. Design and implementation of Android applications using Kotlin and Jetpack Compose. Build and optimize Java backend microservices and REST endpoints. Translate business requirements into technical solutions in collaboration with stakeholders. Act as a technical reference point for team members and guide architectural decisions. Encourage innovation and the adoption of new technologies for operational excellence. Communicate complex technical concepts to non-technical stakeholders effectively. Foster a culture of mentorship and shared learning within the team. Communicate clearly in both Polish and English while adapting language for diverse audiences. KEY REQUIREMENTS: 5+ years of experience in Android development. Proficiency in Kotlin, Google Jetpack Compose, and Android SDK. Hands-on experience with Architecture Components and networking tools such as OkHttp. Strong understanding of Java, Spring and microservices integration. Working knowledge of SQL and experience with unit testing. NICE TO HAVE: Experience in the Fintech industry. Knowledge of Koin DI and MVVM architecture. A proactive mindset and excellent communication skills. OTHER DETAILS: The position is based in Warsaw, within a team structure of 2 developers, 1 tester, a scrum master, a product owner, and business analysts. The work model is hybrid, requiring 2 office days per week, with flexible working hours.

🏢 Summary: Backend Developer role focused on designing, building, and maintaining scalable Java and Kotlin-based applications and microservices within an international team. The position involves developing high-quality backend systems, collaborating with cross-functional teams, and optimizing distributed systems performance. The role emphasizes clean code, modern frameworks, and agile delivery practices. 🗂️ Requirements: 5+ years of backend development experience with Java 8+ and Kotlin, Strong knowledge of Spring Framework and Spring Boot, Experience building RESTful APIs and microservices, Experience with SQL and NoSQL databases, Understanding of Agile/Scrum methodologies 📃 Skills: Java, Kotlin, Spring, SpringBoot, REST, Microservices, SQL, NoSQL, PostgreSQL, MongoDB, Agile, Scrum 🏢 Description: We are looking for skilled Java & Kotlin Developers to join our growing technology team in Poland. As part of an international development group, you’ll design, build, and maintain scalable backend systems using Java and modern frameworks. You’ll collaborate closely with cross-functional teams to deliver high-quality, reliable, and efficient software solutions. Key Responsibilities Design, develop, and maintain Java-based applications and microservices. Write clean, efficient, and testable code following best practices and coding standards. Collaborate with front-end developers , DevOps engineers , and QA teams to ensure seamless integration and delivery. Participate in code reviews , architecture discussions, and agile ceremonies. Contribute to technical documentation and continuous improvement of development processes. Troubleshoot and optimize performance across distributed systems. Requirements 5+ years of experience in backend development using Java 8+ Kotlin . Strong understanding of Spring Framework / Spring Boot . Experience with RESTful APIs , microservices , and SQL / NoSQL databases (e.g., PostgreSQL, MongoDB). Knowledge of Agile / Scrum methodologies. Good command of English (B2 or higher) – Polish language skills are a plus. Nice to Have Experience with cloud platforms (AWS, Azure, or GCP). Familiarity with message brokers (Kafka, RabbitMQ). Knowledge of unit testing and test automation frameworks (JUnit, Mockito). Interest in DevOps or system design concepts. How to Apply If you’re passionate about building high-quality Java applications and want to be part of a dynamic engineering team, send your CV

🏢 Summary: Development role focused on building and maintaining a modern microservices-based payment processing platform in a high-volume environment. The position involves designing, implementing, and supporting Java-based services, ensuring scalability, reliability, and performance. Work is done in a hybrid model with strong emphasis on quality, testing, and production support. 🗂️ Requirements: Minimum 3 years of experience in similar role, Strong Java development experience, Knowledge of Spring Boot, Understanding of microservices architecture, Understanding of distributed systems, Experience with API design, Experience with at least some of the listed technologies, Ability to perform unit testing and code reviews, Fluent English 📃 Skills: Java, Spring, SpringBoot, Microservices, Kubernetes, OpenShift, Kafka, RabbitMQ, MongoDB, Oracle, SQL, REST, Groovy, Maven, Jenkins, Jira, Confluence 🏢 Description: About the Project Our client is a European payments organization undergoing a major digital transformation focused on modernizing its core transaction‑processing platform. The team is building a modern microservices‑based environment designed to increase scalability, reliability, and performance across high‑volume payment operations. Technology stack in use: Java 21 (Spring Boot 3), OpenShift / Kubernetes, Apache Kafka / Rabbit MQ for streaming and queuing, MongoDB, Oracle Database, multiple DevOps tools for development, automation and monitoring. Work mode: hybrid, 3-4 per week from Cracow office Key Responsibilities: ·       Design, develop and support testing payment services features together with the team. ·       Resolve issues by troubleshooting and root cause analysis and support in production issue analysis when needed. ·       Ensure high quality via unit testing and code reviews. ·       Demo and document the results of work in demo sessions. Required Experience & Skills: ·       At least 3 years on similar position ·       Technical knowledge in at least some of the technologies used is needed. ·       Java development skills are the most relevant. ·       Understanding of microservices architecture and distributed systems. ·       Familiarity with API design principles. ·       Fluent English Additional Valuable Skills: ·       Experience in designing and implementing high-throughput, low-latency systems capable of handling large data volumes ·       Groovy, Maven, Jenkins ·       Knowledge of the Card Processing domain ·       Documentation and use of Jira/Confluence ·       Excellent communication and coordination skills We offer Ongoing support from a dedicated agent who is caring about your project continuity, contact with clients, necessary formalities, work comfort, and development. Career Development Program – advice on career planning based on the latest trends and market needs in IT, including consultations with career agents and mentors. Access to 7N Learning & Development – a development and educational platform offering webinars, a library of articles and industry reports, and frequent invitations to both one-time and recurring events focused on technical, business, and lifestyle topics. Spectacular events, both for you (e.g., annual Kick-Off trip , Christmas parties, or Summer Olympics sports events) and for your loved ones (e.g. family picnics), Professional growth Professional growth beyond your current project. You can actively engage in knowledge sharing through the 7N Services offering, designed for 7N clients. Connections and access to the expertise of top IT professionals in the market – the average professional tenure of our consultants in Poland is over 10 years, A complete benefits package, including funding for medical care, life insurance, sports cards for you and your loved ones, as well as discounts in stores in Poland and abroad

🏢 Summary: Mid-Level/Senior Kotlin (Java) Developer role focused on designing and building microservices and APIs within a compliance management platform. The position involves developing backend and web applications in a microservice architecture, contributing to CI/CD processes, and delivering high-quality solutions in an agile environment. Hybrid work model based in Kraków with up to 3 days of remote work per week. 🗂️ Requirements: 4+ years of software development experience, Experience in backend and API development, Proficiency in Kotlin or Java, Experience with API development, Experience with SQL and databases, Experience with HTML and JavaScript, Understanding of microservice architecture, Experience working in Agile environments, Knowledge of Jira and Confluence, Fluent English (B2+ level), Legal right to work in the European Union 📃 Skills: Kotlin, Java, SQL, HTML, JavaScript, Microservices, APIs, CI/CD, Jira, Confluence, AWS, Azure, GCP, Jenkins, Linux, AIX, WebSphere 🏢 Description: Unleash innovation — design cutting-edge microservices and APIs that drive digital transformation! Kraków-based opportunity with hybrid work model (up to 3 days remote per week). As a Mid-Level/Senior Kotlin (Java) Developer , you will be working for our client, a forward-thinking organization building a platform for control owners and development teams to manage and monitor software development compliance. You will contribute to Kotlin and Java-based web applications and APIs within a microservice architecture, supporting innovative solutions across multiple applications and PoCs. This role offers a unique chance to shape the future of development standards while advancing your career in a dynamic environment. Your main responsibilities: Collaborate with cross-functional teams to develop and operate products that meet strategic goals. Design, develop, and implement both front-end and back-end features that support flexible UI frameworks. Build efficient APIs and microservices to address impactful business needs. Work within an agile CI/CD environment to deliver continuous improvements at high velocity. Engage in peer reviews, testing, and automated test scripting to ensure high-quality code. Proactively troubleshoot issues and respond to customer feature requests with innovative solutions. You're ideal for this role if you have: 4+ years of experience in software development, with a focus on backend and API development. Solid expertise in Kotlin or Java (with a willingness to learn Kotlin). Hands-on experience with API development, SQL/databases, and HTML/JavaScript. Strong problem-solving and troubleshooting skills. Experience working in Agile environments with tools like Jira and Confluence. Good understanding of microservice architecture. Excellent interpersonal and communication skills in English (B2+ level). It is a strong plus if you have: Good working knowledge of cloud platforms such as AWS, Azure, or GCP. Experience building CI/CD pipelines using Jenkins. Background in Systems Administration across Linux, AIX, or WebSphere platforms. Language Required for the role: Fluent English (B2+ level). Eligibility to work in Europe: 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.

🏢 Summary: Senior Java Developer role focused on designing, building, and operating scalable fintech backend systems using Java and Spring Boot in cloud environments. The position involves developing high-performance microservices and APIs for payment, trading, and settlement platforms, with end-to-end ownership from architecture to production support. The role requires close collaboration with international teams and ensuring reliability, consistency, and fault tolerance in distributed systems. 🗂️ Requirements: 3–5 years backend development experience, Strong experience with Java, Strong experience with Spring Boot, Experience building scalable backend services and APIs, Knowledge of SQL and NoSQL databases, Understanding of microservices architecture, Understanding of distributed systems, Experience with asynchronous processing, Experience across full SDLC, Experience with AWS or Azure, Professional English proficiency 📃 Skills: Java, SpringBoot, Microservices, SQL, NoSQL, PostgreSQL, MySQL, MongoDB, AWS, Azure, REST, APIs, SDLC, DistributedSystems, AsynchronousProcessing 🏢 Description: Senior Java Developer (Java, Spring Boot, Microservices) Position Overview We are looking for a Senior Java Developer to join our team in Poland and contribute to the development of highly scalable fintech systems supporting trillions of dollars in transactions annually . In this role, you will work closely with the US-based product and engineering teams , helping to design, build, and operate backend services for programmable payment, trading, and settlement platforms. You will report directly to the Software Manager in Poland. A key requirement is excellent English communication skills and strong soft skills — we are looking for someone eloquent, outgoing, friendly, and confident in collaboration . Responsibilities Design and develop backend architecture for fintech products and platforms. Build, maintain, and operate high-performance Java / Spring Boot microservices running in production environments. Develop scalable APIs and backend workflows with strong emphasis on data consistency, fault tolerance, and reliability . Own features end-to-end: from implementation through deployment and production support. Debug and resolve complex issues in distributed systems and high-volume production environments. Work closely with US-based teams to translate product requirements into robust backend solutions. Write clean, maintainable code and contribute to technical documentation, diagrams, and system workflows. Participate in code reviews and continuously improve backend quality and engineering standards. Requirements 3–5 years of professional backend development experience. Strong hands-on experience with Java and Spring Boot in production systems. Proven experience building and maintaining backend services and APIs at scale. Solid understanding of SQL and NoSQL databases (e.g., PostgreSQL/MySQL, MongoDB). Knowledge of microservices architecture, distributed systems, and asynchronous processing. Experience across full SDLC: architecture, development, testing, deployment, and maintenance. Experience operating systems in cloud environments such as AWS or Azure . Excellent communication skills in English . Nice to Have Experience with Spring AI . Previous exposure to banking, payments, trading, or financial transaction systems. Degree in Computer Science or equivalent practical experience. Personal Attributes Highly hands-on engineer who enjoys owning production-grade code. Comfortable working in a fast-paced, startup or high-growth environment. Strong analytical thinking, problem-solving ability, and attention to detail. Clear communicator, confident in collaborating with international teams. Friendly, proactive, and motivated to grow with the company and product.