June 23, 2026
Senior Java Developer
Senior • Remote
120 - 140 PLN/hr
Gliwice, Poland
Join the engineering team to spearhead a critical backend migration from Node.js (Nest.js) to Java/Spring Boot for a specialized Self-Compliance platform. The platform enables enterprise companies to navigate, manage, and enforce labor laws alongside strict regulatory compliance frameworks. In this role, you will work closely with a TechLead and an internal team holding full domain knowledge, transitioning legacy services into a highly scalable, reactive microservices architecture while laying the foundation for long-term product maintenance and feature development.
Details
Start Date: ASAP / Strict July 2026 Start (Only currently available candidates can be considered).
Duration: 6 months or longer.
Max Rate: 140 PLN/h.
Work Allocation: Full-time.
Security & Compliance Constraint: Strictly NO AI tools allowed (Tools like GitHub Copilot, ChatGPT, or similar automated code assistants are completely banned on this project).
Responsibilities
System Migration: Re-architect and migrate the existing backend infrastructure from Nest.js (Node.js) over to Java and Spring Boot.
Microservices & Reactive Design: Implement distributed, fault-tolerant microservices utilizing Netflix OSS and asynchronous, non-blocking reactive programming patterns.
Database & Messaging Integration: Manage data persistence, caching mechanisms, and asynchronous message brokers to maintain high throughput and low-latency system data flow.
Schema Evolution: Write and execute robust database migration scripts to smoothly transition underlying data structures without downtime.
Quality Assurance: Guarantee code stability through thorough unit and integration testing.
Cross-Functional Communication: Collaborate actively in regular project syncs with internal team members, the client, and the TechLead to refine system requirements.
Requirements
Core Backend Stack: Expert commercial knowledge of Java and the Spring Boot ecosystem.
Microservices Architecture: Deep familiarity with Netflix OSS for service discovery, routing, and resilience patterns.
Reactive Programming: Practical experience using Spring Reactor to handle asynchronous data streams.
Data & Cache Layer: Strong hands-on experience with PostgreSQL (relational) and Redis (caching/in-memory data structure store).
Message Broker: Solid proficiency with RabbitMQ for event-driven message queuing.
Database Versioning: Proven experience handling database changes via Liquibase.
Testing Stack: Mastery of JUnit and Mockito for reliable test-driven or test-backed development.
Other Requirements
Languages: Good English proficiency, allowing for smooth daily communication and clear understanding of complex business/legal requirements.
Interpersonal Skills: Outstanding communication and teamwork capabilities for joint ownership of codebases.
Legacy Ecosystem Context: Basic familiarity or comfort reading legacy system layouts spanning Nest.js, React.js, TypeScript, Docker, and Kubernetes is helpful to assist in extraction and migration mapping.
Similar jobs you might like
Technology
emagine Polska
Java Backend Developer
Senior
Remote
Warsaw, Poland
170 - 170 PLN/hr
🏢 Summary: 100% remote B2B contract (up to 170 PLN/h) for a Backend Developer focused on building and evolving microservices-based systems in Java and Spring Boot. The role involves designing REST APIs, implementing secure and reliable inter-service communication, and working with distributed system patterns. You will also contribute to CI/CD pipelines, automated testing, and selected backend components in Node.js within an Agile team. 🗂️ Requirements: Java 17/21 proficiency, Experience with Spring Boot, Ability to design and develop REST API, Knowledge of Node.js, Understanding of microservices architecture, Knowledge of reliability patterns (retry, timeout, circuit breaker), Experience with Docker, Ability to write unit and integration tests (JUnit 5, Mockito, Jest), Experience with relational databases, SQL proficiency, Experience with Git version control 📃 Skills: Java, Spring, SpringBoot, REST, Node.js, TypeScript, Docker, SQL, Git, JUnit, Mockito, Jest, GitHubActions, Microservices 🏢 Description: 100% remote B2B do 170zł/h Start ASAP/do ustalenia Responsibilities: Projektowanie, budowa i rozwój backendu w oparciu o Java 17/21 oraz Spring Boot. Tworzenie i rozwój REST API oraz implementacja mechanizmów bezpieczeństwa. Udział w projektowaniu i utrzymaniu architektury mikroserwisowej. Implementacja komunikacji między serwisami (REST, messaging/event-driven) oraz wzorców niezawodności (retry, timeout, circuit breaker). Praca nad aspektami systemów rozproszonych, takimi jak idempotency, eventual consistency, observability. Konteneryzacja aplikacji za pomocą Docker oraz utrzymanie konfiguracji (Dockerfile, docker-compose). Rozwój wybranych komponentów backendowych w Node.js (TypeScript). Tworzenie i utrzymanie pipeline’ów CI/CD (GitHub Actions). Pisanie testów jednostkowych i integracyjnych (JUnit 5, Mockito, Jest) oraz dbanie o jakość i pokrycie kodu. Współpraca w modelu code review, praca z Git i PR. Udział w pracy zespołu Agile. Must Haves: Znajomość Java 17/21. Doświadczenie z Spring Boot. Umiejętność tworzenia REST API. Znajomość Node.js. Znajomość mikroserwisów oraz wzorców niezawodności. Doświadczenie z Docker. Umiejętność pisania testów jednostkowych i integracyjnych (JUnit 5, Mockito, Jest). Umiejętność pracy z relacyjnymi bazami danych i SQL. Znajomość systemów kontroli wersji (Git). Nice to Haves: Doświadczenie z Adobe AEM 6.5 i integracją backendu z AEM.
Technology
ITDS
Senior Java Spring Boot Backend Developer – Cloud and Microservices
Senior
Hybrid
Krakow, Poland
24,150 - 30,450 PLN
🏢 Summary: Senior Java Spring Boot Backend Developer role focused on building and modernizing a cloud-native Messaging Delivery Platform in the financial sector. The position involves designing and developing scalable microservices, APIs, and distributed systems deployed on Kubernetes and AWS. You will contribute to high-quality backend solutions within an Agile environment using modern DevOps and cloud practices. 🗂️ Requirements: Minimum 6 years of commercial experience in Java development, Strong hands-on experience with Spring Boot, Practical experience in microservices architecture, Experience with Kubernetes and AWS cloud environments, Proficiency with CI/CD tools: Jenkins, GitHub, Maven, Groovy, Strong knowledge of API design: Swagger, OpenAPI, REST, JSON, Experience with OAuth2 and API Gateway solutions such as Kong, Experience with unit testing and TDD practices, Knowledge of Agile methodologies, especially Scrum, Fluent English, Legal right to work in the EU 📃 Skills: Java, Spring, SpringBoot, Microservices, Kubernetes, AWS, Jenkins, GitHub, Maven, Groovy, Swagger, OpenAPI, REST, JSON, OAuth2, Kong, Docker, CICD, TDD, Scrum 🏢 Description: Unleash innovation at scale — drive the future of cloud-native, microservices architectures! Krakow-based opportunity with hybrid work model (3 remote days per week). As a Senior Java Spring Boot Backend Developer , you will be working for our client in the financial industry, focusing on the Messaging Delivery Platform—centralizing and modernizing message delivery to bank customers across multiple channels. Join a cutting-edge project that shapes the future of client communication through advanced distributed systems and cloud technology. Your main responsibilities: Develop high-quality, scalable backend applications using Java and Spring Boot, ensuring adherence to technical requirements and standards. Collaborate within a multidisciplinary Agile team to design, build, and enhance distributed microservices architectures. Implement and monitor API solutions using Swagger, OpenAPI, REST, and JSON standards, ensuring best practices. Deploy and manage containerized applications on Kubernetes, leveraging AWS cloud infrastructure. Integrate authentication and authorization mechanisms such as OAuth 2 and API Gateway solutions. Write and execute unit tests, contribute to automation testing efforts, and uphold quality benchmarks. Participate in code reviews, challenge implementations to maintain highest quality standards, and promote innovation. Keep abreast of current technologies, tools, and industry best practices, continuously enhancing your expertise. Support and mentor team members to foster a culture of technical excellence and knowledge sharing. You're ideal for this role if you have: Minimum 6 years of experience in Java development within a senior or expert capacity. Strong hands-on expertise with Spring Boot framework and microservices architecture. Practical experience with Kubernetes and Cloud environments, particularly AWS. Proficiency with CI/CD tools such as Jenkins, GitHub, Maven, and Groovy scripting. Deep understanding of API design principles, including Swagger, OpenAPI 3.0, REST, and JSON. Familiarity with authentication protocols like OAuth 2 and API Gateway solutions such as Kong. Robust knowledge of Agile practices, especially TDD and Scrum methodologies. Ability to work fluently in English, with excellent communication skills. It is a strong plus if you have: Certifications or additional experience with AWS services. Knowledge of automation testing frameworks. Experience with messaging systems or middleware. 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.
Technology
ITDS
Senior Java Spring Boot Backend Developer – Cloud and Microservices
Senior
Hybrid
Krakow, Poland
24,150 - 30,450 PLN
🏢 Summary: Senior Java Spring Boot Backend Developer role focused on building and modernizing a cloud-native Messaging Delivery Platform in the financial sector. The position involves designing and developing scalable microservices, APIs, and distributed systems deployed on Kubernetes and AWS. You will work in an Agile team to deliver secure, high-quality backend solutions for multi-channel customer communication. 🗂️ Requirements: Minimum 6 years of Java development experience, Strong hands-on experience with Spring Boot, Experience designing microservices architectures, Practical experience with Kubernetes, Experience with AWS cloud environments, Proficiency with CI/CD tools (Jenkins, GitHub, Maven, Groovy), Strong knowledge of API design (Swagger, OpenAPI, REST, JSON), Experience with OAuth2 and API Gateway solutions (Kong), Experience with TDD and Scrum methodologies, Legal right to work in the European Union 📃 Skills: Java, Spring, SpringBoot, Microservices, Kubernetes, AWS, Jenkins, GitHub, Maven, Groovy, Swagger, OpenAPI, REST, JSON, OAuth2, Kong, CICD, TDD, Scrum, API 🏢 Description: Unleash innovation at scale — drive the future of cloud-native, microservices architectures! Krakow-based opportunity with hybrid work model (3 remote days per week). As a Senior Java Spring Boot Backend Developer , you will be working for our client in the financial industry, focusing on the Messaging Delivery Platform—centralizing and modernizing message delivery to bank customers across multiple channels. Join a cutting-edge project that shapes the future of client communication through advanced distributed systems and cloud technology. Your main responsibilities: Develop high-quality, scalable backend applications using Java and Spring Boot, ensuring adherence to technical requirements and standards. Collaborate within a multidisciplinary Agile team to design, build, and enhance distributed microservices architectures. Implement and monitor API solutions using Swagger, OpenAPI, REST, and JSON standards, ensuring best practices. Deploy and manage containerized applications on Kubernetes, leveraging AWS cloud infrastructure. Integrate authentication and authorization mechanisms such as OAuth 2 and API Gateway solutions. Write and execute unit tests, contribute to automation testing efforts, and uphold quality benchmarks. Participate in code reviews, challenge implementations to maintain highest quality standards, and promote innovation. Keep abreast of current technologies, tools, and industry best practices, continuously enhancing your expertise. Support and mentor team members to foster a culture of technical excellence and knowledge sharing. You're ideal for this role if you have: Minimum 6 years of experience in Java development within a senior or expert capacity. Strong hands-on expertise with Spring Boot framework and microservices architecture. Practical experience with Kubernetes and Cloud environments, particularly AWS. Proficiency with CI/CD tools such as Jenkins, GitHub, Maven, and Groovy scripting. Deep understanding of API design principles, including Swagger, OpenAPI 3.0, REST, and JSON. Familiarity with authentication protocols like OAuth 2 and API Gateway solutions such as Kong. Robust knowledge of Agile practices, especially TDD and Scrum methodologies. Ability to work fluently in English, with excellent communication skills. It is a strong plus if you have: Certifications or additional experience with AWS services. Knowledge of automation testing frameworks. Experience with messaging systems or middleware. 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.
Technology
ITDS
Senior Java Spring Boot Backend Developer – Cloud and Microservices
Senior
Hybrid
Krakow, Poland
24,150 - 30,450 PLN
🏢 Summary: Senior Java Spring Boot Backend Developer role focused on building and modernizing a cloud-native Messaging Delivery Platform in the financial sector. The position involves developing scalable microservices, APIs, and containerized applications deployed on AWS using Kubernetes. It combines hands-on backend engineering with DevOps practices in an Agile environment. 🗂️ Requirements: Minimum 6 years of Java development experience, Strong hands-on experience with Spring Boot, Experience with microservices architecture, Practical experience with Kubernetes, Experience with AWS cloud environment, Experience with CI/CD tools (Jenkins, GitHub, Maven, Groovy), Strong knowledge of API design (REST, Swagger, OpenAPI, JSON), Experience with OAuth2 and API Gateway solutions, Experience working in Agile (Scrum, TDD), Legal right to work in the European Union 📃 Skills: Java, Spring, SpringBoot, Microservices, Kubernetes, AWS, Jenkins, GitHub, Maven, Groovy, REST, Swagger, OpenAPI, JSON, OAuth2, Kong, CI/CD, TDD, Scrum 🏢 Description: Unleash innovation at scale — drive the future of cloud-native, microservices architectures! Krakow-based opportunity with hybrid work model (3 remote days per week). As a Senior Java Spring Boot Backend Developer , you will be working for our client in the financial industry, focusing on the Messaging Delivery Platform—centralizing and modernizing message delivery to bank customers across multiple channels. Join a cutting-edge project that shapes the future of client communication through advanced distributed systems and cloud technology. Your main responsibilities: Develop high-quality, scalable backend applications using Java and Spring Boot, ensuring adherence to technical requirements and standards. Collaborate within a multidisciplinary Agile team to design, build, and enhance distributed microservices architectures. Implement and monitor API solutions using Swagger, OpenAPI, REST, and JSON standards, ensuring best practices. Deploy and manage containerized applications on Kubernetes, leveraging AWS cloud infrastructure. Integrate authentication and authorization mechanisms such as OAuth 2 and API Gateway solutions. Write and execute unit tests, contribute to automation testing efforts, and uphold quality benchmarks. Participate in code reviews, challenge implementations to maintain highest quality standards, and promote innovation. Keep abreast of current technologies, tools, and industry best practices, continuously enhancing your expertise. Support and mentor team members to foster a culture of technical excellence and knowledge sharing. You're ideal for this role if you have: Minimum 6 years of experience in Java development within a senior or expert capacity. Strong hands-on expertise with Spring Boot framework and microservices architecture. Practical experience with Kubernetes and Cloud environments, particularly AWS. Proficiency with CI/CD tools such as Jenkins, GitHub, Maven, and Groovy scripting. Deep understanding of API design principles, including Swagger, OpenAPI 3.0, REST, and JSON. Familiarity with authentication protocols like OAuth 2 and API Gateway solutions such as Kong. Robust knowledge of Agile practices, especially TDD and Scrum methodologies. Ability to work fluently in English, with excellent communication skills. It is a strong plus if you have: Certifications or additional experience with AWS services. Knowledge of automation testing frameworks. Experience with messaging systems or middleware. 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.
Technology
RITS Professional Services
Senior Node.js Developer
Senior
Remote
Warsaw, Poland
40 - 50 PLN/hr
🏢 Summary: Remote Senior Backend Node.js Developer role focused on building and scaling an event-driven microservices trading platform. The position involves end-to-end development, collaborating across product, QA, and DevOps to deliver high-performance, scalable trading solutions. B2B contract with overlap required with NYC working hours. 🗂️ Requirements: Bachelor’s Degree in Computer Science or related field, 3-5 years professional web application development experience, Expert-level Node.js knowledge, Expert-level TypeScript knowledge, Experience with distributed systems, Experience with Apache Kafka, Redis, Kubernetes, MongoDB, Experience with automated unit testing and TDD, Strong understanding of performance optimization and computational complexity, Knowledge of algorithms and design patterns, Fluent English (written and spoken) 📃 Skills: Node.js, TypeScript, Kafka, Redis, Kubernetes, MongoDB, Microservices, TDD, Algorithms, DesignPatterns, Web, DistributedSystems 🏢 Description: We are looking for a performance-driven backend Senior Node.js Developer who can help us bring our client's trading solutions to the next level of functionality, scalability, and user experience. They are actively developing a new event-driven microservices architecture to form a foundational platform for delivering new trading applications. You will be responsible for delivering software end-to-end , from liaising with product managers and designers, to coordinating across international development teams on engineering and architecture to working with QA and DevOps teams - all ultimately to deliver a quality, innovative product to the traders and investors who depend on the platform every day. Requirements: Fluent English language [both written and spoken] Education: at least Bachelor's Degree, preferably in Computer Science 3-5 years' professional web application development experience Expert-level Node.js and TypeScript knowledge, and curiosity to learn more Broad knowledge of web platform and technologies Superior analytical and problem-solving ability Effective communication skills to work with different teams across an international company Experience with modern distributed systems and infrastructure technologies, including Apache Kafka, Redis, Kubernetes, and MongoDB Automated unit testing and test-driven development Robust understanding of performance issues, computational complexity, and code optimization. Familiarity and implementation of industry-standard algorithms and design patterns Proactive and team player who can deliver in a high-pressure demanding environment Nest.js – nice to have Offer details: 100% remote job preferrably at least 4-5 hours overlap with NYC working hours B2B contract rate up to 50 USD/h net Don't hesitate and apply now!
Technology
DCV Technologies
Middle Java backend
Mid
Hybrid
Warsaw, Poland
900 - 950 PLN
🏢 Summary: The offer is for a Java Backend Developer role focused on building and maintaining microservices-based systems using Java and Spring technologies. The position involves developing REST APIs, working with containerized applications, and contributing to Agile delivery processes. The role centers on backend engineering, technical design, and collaboration within cross-functional teams. 🗂️ Requirements: Minimum 3+ years professional experience in backend development, Proficiency in Java 8+, Strong experience with Spring Boot and Spring technologies, Experience building microservices, Experience working with REST APIs, Knowledge of HTTPS, SFTP, REST and SOAP protocols, Understanding of microservices architecture and containerization, Experience with Kafka, Experience with Git and GitHub, Experience with Maven and Jenkins, Experience with MySQL and SQL databases, Familiarity with Linux, Experience working in Agile/Scrum environments 📃 Skills: Java, Spring, SpringBoot, REST, Microservices, Kafka, HTTPS, SFTP, SOAP, Linux, Git, GitHub, Maven, Jenkins, Jira, MySQL, SQL, Containerization, Agile 🏢 Description: Job Description: We are looking for skilled Java Backend Developers with strong experience in Java, Spring technologies, and microservices architecture. The ideal candidate will have hands-on expertise in backend development, REST APIs, containerized applications, and Agile delivery environments. Qualifications: Minimum 3+ years of relevant professional experience Proficiency in Java 8+, REST APIs, Spring Boot, and Spring technologies Experience in building microservices and working with Kafka Solid understanding of HTTPS, SFTP, REST API, and SOAP protocols Familiarity with Linux operating systems Strong understanding of microservices architecture and containerization Knowledge of Agile frameworks and principles Experience with Git/GitHub, GitHub Actions, Maven, Jenkins, and Jira Competence with MySQL and SQL databases Strong analytical and problem-solving skills Excellent written and verbal communication skills Ability to collaborate effectively with Product, QA, DevOps, and Agile/Scrum teams Mandatory Skills: Java (Spring) REST APIs Spring Boot and Spring Technologies HTTPS, SFTP, REST API, and SOAP protocols Microservices architecture and containerization Git/GitHub, GitHub Actions, Maven, Jenkins, Jira MySQL and SQL databases Desired Skills: Strong analytical and troubleshooting abilities Excellent communication skills Team collaboration experience within Agile/Scrum environments Roles & Responsibilities: Contribute to technical design and engineering activities Develop strong domain expertise within the project Analyse functional and technical requirements Support architecture and design discussions Collaborate with Architecture and Business teams Participate in development, design, code reviews, and implementation Follow engineering best practices and support continuous improvement initiatives Out of Scope: Creating product requirements Acting as Scrum Master or Product Owner Project Details: Primary focus is on Java backend development.
Technology
Awareson Sp. z o.o.
Senior Java Developer (Kafka/Security)
Senior
Remote
Warsaw, Poland
140 - 170 PLN/hr
🏢 Summary: Remote B2B opportunity for a Senior Backend Engineer to design and develop scalable microservices-based backend systems using Java and Spring Boot in a cloud environment. The role focuses on building REST APIs, integrating messaging systems, and ensuring high availability, security, and scalability of distributed systems. The project is expanding and requires experienced engineers to support its growing scale. 🗂️ Requirements: Minimum 5 years of experience in backend development with Java, Very good knowledge of Java 17 or newer (preferably Java 21), Practical experience with Spring Boot and Spring ecosystem (Spring Security, Spring Data, WebFlux or MVC), Experience in designing and developing distributed systems and microservices, Experience with asynchronous communication tools (Kafka or RabbitMQ), Very good knowledge of PostgreSQL and SQL, Experience in designing and integrating REST APIs, Practical knowledge of AWS or GCP cloud environments, Experience with Docker and Kubernetes, Knowledge of application security, including data encryption, token handling, and PCI-DSS basics, Communicative English level 📃 Skills: Java, Spring, SpringBoot, SpringSecurity, SpringData, WebFlux, MVC, Kafka, RabbitMQ, PostgreSQL, SQL, REST, AWS, GCP, Docker, Kubernetes, Microservices, PCI-DSS 🏢 Description: Dla naszego klienta z branży logistycznej poszukujemy dwóch doświadczonych Senior Backend Engineerów, którzy dołączą do zespołu rozwijającego nowoczesne rozwiązania backendowe w środowisku opartym o architekturę mikroserwisową oraz technologie chmurowe.Rekrutacja wynika z rozwoju projektu i potrzeby zwiększenia jego skali. Lokalizacja: praca zdalna oraz raz na kwartał spotkanie w Krakowie Forma współpracy: B2B Stawka: do 170 PLN/h Język angielski: minimum poziom komunikatywny Zakres obowiązków Projektowanie, rozwój i utrzymanie aplikacji backendowych opartych o Javę i Spring Boot Tworzenie oraz rozwijanie architektury mikroserwisowej Projektowanie i implementacja interfejsów REST API Integracja systemów z wykorzystaniem brokerów wiadomości Współpraca przy projektowaniu rozwiązań zapewniających wysoką dostępność i skalowalność systemów Udział w procesach związanych z bezpieczeństwem aplikacji oraz ochroną danych Współpraca z zespołami produktowymi, architektami oraz innymi zespołami technologicznymi Wymagania Minimum 5 lat doświadczenia zawodowego w tworzeniu aplikacji backendowych w języku Java Bardzo dobra znajomość Java 17 lub nowszej wersji (preferowana Java 21) Praktyczne doświadczenie z frameworkiem Spring Boot oraz komponentami ekosystemu Spring (Spring Security, Spring Data, WebFlux lub MVC) Doświadczenie w projektowaniu i rozwijaniu systemów rozproszonych oraz mikroserwisów Znajomość narzędzi do komunikacji asynchronicznej, takich jak Kafka lub RabbitMQ Bardzo dobra znajomość PostgreSQL oraz języka SQL Doświadczenie w projektowaniu i integracji REST API Praktyczna znajomość środowisk chmurowych AWS lub GCP Doświadczenie w pracy z Dockerem oraz Kubernetesem Znajomość zagadnień związanych z bezpieczeństwem aplikacji, w tym szyfrowaniem danych, obsługą tokenów oraz podstawowych wymagań PCI-DSS Komunikatywna znajomość języka angielskiego Mile widziane Doświadczenie zdobyte w branży fintech, płatności lub e-commerce Znajomość standardów PCI-DSS, PSD2 lub ISO 8583 Doświadczenie w pracy z rozwiązaniami opartymi o modele językowe (OpenAI, Anthropic lub podobne) Znajomość zagadnień związanych z RAG, Prompt Engineering, Tool Use lub innymi wzorcami Agentic AI Doświadczenie w integracji systemów płatniczych, widgetów lub SDK
Technology
P&P Solutions
JVM Software Engineer
Mid
Hybrid
Warsaw, Poland
90 - 120 PLN/hr
🏢 Summary: Long-term B2B opportunity for a Senior Java Developer to modernize and develop a large-scale CRM platform, focusing on migrating a legacy JBoss monolith to a Spring Boot-based domain-driven architecture. The role involves backend development, system modernization, database migration, and collaboration within cross-functional teams. Work is delivered in a hybrid model within an established development department. 🗂️ Requirements: Commercial experience with Java 21+, Experience with REST API development, Strong knowledge of Spring and Spring Boot, Experience with unit and integration testing (Mockito, Testcontainers, JUnit 5), Proficiency with Git, Experience using Swagger, Ability to work with IntelliJ, Experience with JBoss or JEE5, Knowledge of SQL (Postgres or Sybase), English level B2/C1 📃 Skills: Java, REST, Spring, SpringBoot, JUnit, Mockito, Testcontainers, Git, Swagger, IntelliJ, JBoss, JEE, SQL, Postgres, Sybase, React, Kubernetes, Jenkins, JBPM, Swing, JavaFX 🏢 Description: Client: A leading German telecommunications and IT corporation Start date: ASAP Locations: Warszawa, Poznań, Lublin Work model: hybrid with 3 days/week from the office Engagement: Long-term Form of cooperation: B2B, full-time Working hours: Standard business hours About our client: A leading German telecommunications and IT corporation, recognized for innovative solutions in cloud computing, web hosting, and internet services, is expanding its European Technology Center in Poland. The company is building strong development teams in Warsaw, Poznan, and Lublin to support its long-term digital transformation initiatives. About the project & team: You will join an established development team consisting of three experienced Java developers and one test manager. This team is part of a larger department that includes over 20 developers across several cross‑functional teams. The department is responsible for the company’s core CRM platform, which includes multiple frontends (Java Swing, JavaFX, React) and numerous backend services built in technologies such as JBoss 4/7, WildFly 10, Spring Boot, and Spring Batch. The primary focus of your future team is the modernization of the CRM system, including the migration of business logic from a legacy monolithic JBoss 4 application to a modern, domain‑driven architecture using Spring Boot. Future development includes building new React-based frontends, enhancing backend services, and modernizing database layers (e.g., Sybase migrations). You will work within a stable, collaborative setup, contributing to high-impact solutions used across the organization. Must‑have skills: Java >21 REST Spring / Spring Boot Unit- and Integrations-Tests (Mockito, Testcontainers, JUnit 5) Git Swagger IntelliJ Nice to have skills: Kubernetes JEE5 (JBOSS) SQL (Optimal: Postgres, Sybase) Java Swing or JavaFX JBPM Jenkins (CI/CD) English Level: B2/C1 Responsibilities: Develop and maintain backend services within a large CRM platform. Migrate business logic from a monolithic JBoss 4 system to Spring Boot microservices. Participate in building new frontends (React) and extending backend functionalities. Contribute to database modernization, including migration of Sybase logic. Collaborate closely with developers and the team’s test manager. Ensure high code quality through unit and integration testing. Use best practices in CI/CD, version control, and modern development standards. What We Offer: Competitive compensation: up to 120 PLN/h netto on a B2B contract Flexible settlements: Payments issued in your preferred form Fast invoicing: Short 14‑day payment terms Comprehensive healthcare: Extended private medical care package My Benefit platform: Access to a cafeteria system including Multisport cards and prepaid vouchers (e.g., IKEA, Zalando, Notino, and more)
Technology
RITS Professional Services
Senior Node.js Developer
Senior
Remote
Warsaw, Poland
26,880 - 29,400 PLN/hr
🏢 Summary: Senior Backend Node.js Developer role focused on building and scaling an event-driven microservices trading platform. The position involves end-to-end development within a distributed architecture, ensuring high performance, scalability, and code quality. Fully remote B2B contract with overlap with NYC hours. 🗂️ Requirements: 4+ years web application development experience, Expert knowledge of Node.js, Expert knowledge of TypeScript, Experience with distributed systems architecture, Experience with Apache Kafka, Experience with Redis, Experience with Kubernetes, Experience with MongoDB, Experience with automated unit testing and TDD, Strong understanding of performance optimization and computational complexity, Knowledge of algorithms and design patterns, Broad knowledge of web technologies 📃 Skills: Node.js, TypeScript, Kafka, Redis, Kubernetes, MongoDB, Microservices, TDD, Algorithms, DesignPatterns, Web 🏢 Description: We are looking for a performance-driven backend Senior Node.js Developer who can help us bring our client's trading solutions to the next level of functionality, scalability, and user experience. They are actively developing a new event-driven microservices architecture to form a foundational platform for delivering new trading applications. You will be responsible for delivering software end-to-end , from liaising with product managers and designers, to coordinating across international development teams on engineering and architecture to working with QA and DevOps teams - all ultimately to deliver a quality, innovative product to the traders and investors who depend on the platform every day. Requirements: Fluent English language [both written and spoken] Education: at least Bachelor's Degree, preferably in Computer Science 4+ years' professional web application development experience Expert-level Node.js and TypeScript knowledge, and curiosity to learn more Broad knowledge of web platform and technologies Superior analytical and problem-solving ability Effective communication skills to work with different teams across an international company Experience with modern distributed systems and infrastructure technologies, including Apache Kafka, Redis, Kubernetes, and MongoDB Automated unit testing and test-driven development Robust understanding of performance issues, computational complexity, and code optimization. Familiarity and implementation of industry-standard algorithms and design patterns Proactive and team player who can deliver in a high-pressure demanding environment Nest.js – nice to have Offer details: 100% remote job preferrably at least 4-5 hours overlap with NYC working hours B2B contract rate up to 55 USD/h net
Technology
DataArt
Senior Backend Engineer with Java
Senior
Remote
Wroclaw, Poland
16,000 - 19,000 PLN
🏢 Summary: Senior Backend Engineer role focused on defining the technical direction and architecture of a domain within a borderless financial platform. The position involves designing scalable microservices, driving architectural decisions, and leading a small backend team in a distributed environment. The role emphasizes reliability, security, and high‑volume transaction processing in a cloud-based ecosystem. 🗂️ Requirements: 4-7 years backend engineering experience, Proficiency in Go, Experience with Java 21 or modern Java, Experience designing microservices with clear contracts, Experience with caching strategies including TTL and invalidation, Experience with event-driven or asynchronous architectures, Experience with structured logging, metrics, and alerting, Experience with AWS services, Experience with relational and non-relational databases, Experience with Spring Boot or similar frameworks, Experience reviewing code and architectural decisions, Availability to work in GMT+5:30 timezone 📃 Skills: Java, Go, Spring, JDBI, PostgreSQL, CockroachDB, DynamoDB, Redis, SQS, SNS, Kafka, AWS, EKS, ALB, RDS, S3, Kong, Datadog, Quickwit, JWT, RBAC, TLS, Docker, ArgoCD, GitHub, Microservices, Kafka, CDC 🏢 Description: Project overview This project focuses on developing a borderless financial platform that supports international banking flows, payments, account management and regulatory compliant operations. The product handles sensitive data and high volume transactions while prioritising reliability and security. Team You will work in a distributed environment with backend engineers, a product manager and platform specialists. The role involves leading a sub team of three to five engineers, conducting design reviews, ensuring code quality standards and supporting collaborative decision making. Position overview We are looking for a Senior Backend Engineer who will define the technical direction of a backend domain and drive architectural decisions. You will design microservices, create scalable solutions, guide a small engineering group and collaborate closely with product specialists to shape the delivery roadmap. We are looking for a person willing to work in the time zone: GMT+5:30. Technology stack Java 21, Go, Spring Boot, JDBI, custom workflow engines, PostgreSQL, CockroachDB, DynamoDB, Redis, SQS, SNS, Kafka, AWS EKS ALB RDS S3 Secrets Manager, Kong API Gateway, Datadog, Quickwit, JWT RBAC TLS request and response encryption VAPT, GitHub Actions, Docker, ArgoCD, microservices, event driven architecture, saga and orchestration patterns, CDC pipelines, maker checker workflows Responsibilities Plan and design backend microservices with clear boundaries and contracts Develop solutions for domains such as onboarding, payments, transaction orchestration or platform components Break complex epics into actionable tasks with clear acceptance criteria Review designs from other engineers to ensure scalability and fault tolerance Drive technical decisions including caching layers, asynchronous processing strategies, database choices and API versioning Evaluate build versus buy options for integrations and services Collaborate with a product manager to align on scope and prioritisation Lead a sub team of backend engineers and support their professional growth Support incident response, root cause analysis and long term improvements Monitor service performance using logging, metrics and tracing tools Requirements Professional backend engineering experience from 4-7 years Experience with Go (tooling & CLIs) Experience designing microservices with well-defined contracts and boundaries Experience with Java 21 or modern Java versions Experience with caching strategy design, including TTL and invalidation approaches Experience working with asynchronous processing, event-driven architecture, or queue-based workflows Experience using structured logging, metrics, and alerting to debug production systems Experience in making build versus buy decisions with clear trade-off analysis Experience reviewing code and identifying architectural or contract issues Experience with AWS-based services Experience working with relational and non-relational databases such as PostgreSQL or DynamoDB Experience writing backend services using Spring Boot or similar frameworks Nice to have Experience with financial or payments related systems Experience with KYC or AML flows Experience with workflow or orchestration engines Experience with platform wide pattern creation or reusable service design Experience with data encryption practices and security audits Experience with CockroachDB or high availability distributed databases What We Offer: Vacation days : Up to 26 business days per year. 10 illness/special days off per year (fully paid, no medical papers needed) for all contract types Health and life insurance (Luxmed) MyBenefit platform with Multisport option Internal psychological support service English language classes from the first working day Access to external learning platforms : O’Reilly, LinkedIn Learning, Udemy, and a wide catalog of diverse internal training Flexible workplace : work from the office, from home, or choose a hybrid option Tech Skills Mentoring Program Opportunities to develop as a public speaker, mentor, or technical interviewer Fully paid idle (bench) when not involved in a project Certification reimbursement (AWS, GCP, Microsoft, etc.)