Senior Backend Engineer (Java, Kafka Streams, AWS)

🏢 Summary: Staff Engineer role focused on leading the design, evolution, and reliability of a high-scale distributed backend platform that generates and distributes real-time customer offers. The position combines deep hands-on backend engineering with architectural leadership in event-driven systems. It emphasizes scalability, performance, observability, and operational excellence in a complex production environment. 🗂️ Requirements: Experience owning complex backend systems end-to-end in scalable production environments, Proven experience designing and operating distributed systems, Strong backend engineering expertise in Java, Solid understanding of JVM performance, Hands-on experience with Apache Kafka, Hands-on experience with Spring Boot and/or Vert.x, Hands-on experience with Redis, Hands-on experience with OpenSearch or Elasticsearch, Experience with observability tools such as Datadog, Grafana, or Kibana, Strong system design skills in event-driven and asynchronous architectures, Knowledge of concurrency and non-blocking system design, Experience with scalability, resiliency, and fault-tolerance strategies, Experience debugging production incidents in distributed environments 📃 Skills: Java, JVM, Kafka, Spring, Vert.x, Redis, OpenSearch, Elasticsearch, Datadog, Grafana, Kibana, Kubernetes 🏢 Description: ABOUT THE ROLE We are looking for a passionate and highly experienced Staff Backend Engineer to help lead the design, development, reliability, and evolution of a complex distributed backend platform. This role is ideal for someone who enjoys going deep into understanding both the technical and business context behind problems, not just implementing solutions mechanically. We value engineers who are curious, proactive, and driven by learning - people who enjoy experimenting, challenging assumptions, and troubleshooting complex systems until the root cause is fully understood. As a Staff Backend Engineer, you will provide technical leadership across architecture, engineering practices, and platform evolution while remaining hands-on when needed. You will help teams make better technical decisions, raise engineering standards, simplify complex systems, and create solutions that balance business needs with long-term platform health. We're looking for someone who is comfortable working in ambiguity, treats failure as an opportunity to learn, welcomes constructive feedback, and leads through collaboration, ownership, and execution rather than authority. ABOUT YOUR FUTURE PLATFORM TEAM We build and operate a critical backend platform that generates, validates, and distributes customer-facing offers across multiple markets in real time. The system sits at the intersection of pricing, configuration, compliance, and localization - where milliseconds matter, correctness is non-negotiable, and small mistakes can have large-scale impact. Our systems apply complex configuration and licensing rules, handle market and event-level blocking, manage multi-language localization, and transform raw pricing data into customer-ready offers consumed across the ecosystem. We process high-throughput event streams, deal with constantly changing data, and solve problems that require both strong engineering fundamentals and deep domain understanding. Success means no incorrect or missing offers in production, near real-time reflection of pricing and configuration changes, fully compliant offers across jurisdictions, and seamless multi-language experiences for customers. Our ecosystem is built around: Event streaming and backbone: Apache Kafka Backend services: Java 23+ with Spring Boot and Vert.x (we are continuously evolving toward highly reactive, asynchronous, and event-driven architecture) State and performance optimization: Redis Search and analytics: OpenSearch / Elasticsearch Observability and operations: Datadog, Grafana, Kibana Runtime and scalability: Kubernetes-based containerized infrastructure We are actively evolving our platform toward more reactive, asynchronous, and event-driven architectures, making this an exciting environment for engineers who enjoy distributed systems, performance, concurrency, and real-time data processing challenges. WHAT YOU'LL DO Technical Leadership Leading architecture and design discussions for scalable, resilient distributed systems Collaborating with Architects and senior engineers to define solution approaches and evaluate new technologies through spikes and PoCs Improving and simplifying existing system designs while maintaining high engineering standards for performance, correctness, and maintainability Maintaining a strong engineering bar across quality, scalability, and maintainability Platform Reliability & Engineering Excellence Proactively identifying scalability, reliability, and performance risks across the platform Leading debugging and root cause analysis for complex production incidents Improving observability, monitoring, alerting, and operational readiness Driving technical debt reduction and continuous platform improvement Promoting best practices across event-driven systems, resiliency patterns, performance optimization, testing, automation, and CI/CD Team Enablement & Collaboration Supporting day-to-day technical coordination within the team and contributing to incident handling and engineering discussions Mentoring engineers through design reviews, code reviews, and hands-on technical guidance Supporting cross-team collaboration and helping troubleshoot integration and platform issues Encouraging a culture of collaboration, clarity, and shared ownership Actively participating in engineering communication channels and helping unblock others Delivery & Execution Working closely with Product, Engineering Managers, and Architects to translate ideas into executable technical solutions Helping define and break down EPICs and technical initiatives in Jira Driving clarity in ambiguous or complex technical initiative Ensuring alignment between short-term delivery needs and long-term platform evolution WHAT WE'RE LOOKING FOR Required Experience: Experience owning complex backend systems end-to-end in scalable production environments Proven experience designing and operating distributed systems Strong backend engineering expertise in Java, with solid understanding of JVM performance Hands-on experience with: Apache Kafka and event-driven architectures Spring Boot and/or Vert.x Redis for low-latency and stateful use cases OpenSearch / Elasticsearch for querying and analytics Observability tools such as Datadog, Grafana, or Kibana Strong system design skills, including: Event-driven and asynchronous architectures Concurrency and non-blocking system design Scalability, resiliency, and fault-tolerance strategies Evaluating trade-offs between latency, throughput, and consistency Experience debugging production incidents in distributed environments Strong communication skills and ability to influence technical decisions across teams Proactive mindset with strong ownership and accountability Comfortable working in complex, fast-paced engineering environments Collaborative approach and willingness to support and mentor others Nice to Have: Kubernetes and cloud-native infrastructure experience Experience building internal platforms or shared engineering frameworks SRE mindset and operational excellence practices Experience with real-time or high-throughput data systems Experience leading cross-team technical initiatives WHAT SUCCESS LOOKS LIKE Teams rely on you for technical direction and practical problem-solving The platform becomes more reliable, scalable, and easier to operate over time Production incidents decrease due to proactive engineering and improved system design Cross-team dependencies are better coordinated and easier to manage Engineering quality and consistency improve across services and squads Engineers grow technically through your mentorship and guidance WHAT WE OFFER Competitive salary aligned with your experience, expertise, and impact A collaborative, inclusive, and fast-paced engineering environment where ideas are welcomed, ownership is encouraged, and continuous learning is valued Hybrid work policy 4 weeks of Workation (T&C apply) Benefits package - 800 PLN net (B2B)/gross (UOP) monthly with access to the cafeteria platform (private medical care, insurances, sports card) Training budget ICAS assistance program that can provide help and guidance during challenging moments. Our office provides complimentary snacks and drinks; on Mondays, we serve complimentary breakfast. Team and office social events throughout the year Free parking for bicycles and motorcycles Free gym in the building Equipment: MacBook Pro + smartphone (iPhone 16/17 or Samsung Galaxy S25)

🏢 Summary: Senior or Staff Backend Engineer role focused on architecting and scaling AI-native backend systems for a modern accounting platform. The position involves designing distributed services, building high-performance APIs, and establishing engineering standards to support rapid, reliable product delivery. You will work closely with Product, AI, and Operations teams to develop agentic systems and scalable data pipelines. 🗂️ Requirements: 5–10+ years of backend engineering experience, Proven experience designing, building, and operating production backend systems at scale, Strong expertise in API design, Strong expertise in data modelling, Deep understanding of distributed systems trade-offs, Hands-on experience with AWS or GCP in production, Practical experience with CI/CD in high-frequency deployment environments, Experience implementing testing and deployment strategies, Strong knowledge of observability practices, Experience participating in on-call rotations 📃 Skills: TypeScript, Node.js, React, AWS, GCP, Terraform, PostgreSQL, OpenAI, Azure, CI/CD, APIs, DistributedSystems 🏢 Description: ABOUT THE ROLE We're looking for a Senior or Staff Backend Engineer to own and evolve our backend services as we scale. This is a broad, high-impact role — you'll architect new features, build the systems that underpin our core product, and set the engineering standards that shape how the whole team works. The focus is on building a modern, AI-native developer experience. That means working closely with Product, AI, and Operations teams to design agentic systems, distributed data pipelines, and scalable incident response infrastructure — and doing it in a way that lets the team ship with confidence multiple times a day. WHAT YOU'LL WORK ON Architecture and feature design Partner with Product, AI, and Operations teams to architect new features and complex agentic systems. Make clear architectural trade-offs that balance platform, product, and business goals. Backend services and APIs Build and maintain the backend services and APIs that power the core product. Ensure systems are secure, well-tested, and high performance. Distributed systems Design and implement distributed services to orchestrate data pipelines, automate investigations, and enable incident response at scale. Operational excellence Own operational best practices so the team can ship multiple times a day with confidence. Healthy on-call culture and strong observability are part of what you'll build and maintain. Engineering standards Set the bar for writing, communication, and system design across the team. Your influence will shape how a modern AI-native product is built. WHAT WE LOOK FOR 5–10+ years of backend engineering experience A strong track record designing, building, and operating production backend systems at scale. Deep backend fundamentals Expertise in API design, data modelling, and reasoning about distributed systems trade-offs. You understand the nuances, not just the patterns. AWS or GCP hands-on experience Solid understanding of how infrastructure decisions impact application reliability and performance. You've run things in production, not just designed them. CI/CD in practice Practical experience with testing and deployment strategies in high-frequency shipping environments. Observability and on-call maturity A solid grasp of what good observability looks like and how to build healthy on-call practices that don't burn people out. Bonus Experience at an early-stage or scaling startup. Exposure to modern AI and ML systems. Experience shipping product without a dedicated product manager. TECH STACK TypeScript, React, Node.js, AWS, Terraform, PostgreSQL, OpenAI, Azure AI. The team uses GitHub, Slack, Linear, Figma, and Notion day to day. THE TEAM Small, senior, and in-person. The office is in central Wrocław, next to the main train station. The expectation is 4–5 days a week in the office. Relocation support is available for the right candidate. COMPENSATION & BENEFITS Salary $130,000 – $190,000 USD depending on experience, plus competitive equity. Wellness and commute stipend $100 per month. Hardware Premium hardware provided — MacBook Pro and AirPods. Food Daily in-office lunch and dinner. Time off 20 PTO days plus 9 US public holidays. Relocation Support available for candidates relocating to Wrocław.

🏢 Summary: Backend engineering role focused on designing and scaling assortment management systems in a distributed retail environment using Kotlin, Spring Boot, Kafka, AWS, and Kubernetes. The position involves leading backend architecture, building event-driven integrations, optimizing system reliability, and collaborating with product and engineering stakeholders. Candidates will also mentor engineers and drive best practices across scalable cloud-native platforms. 🗂️ Requirements: Degree in Computer Science or related technical field, 6+ years of backend development experience, Experience with Kotlin, Experience with Spring Boot, Strong knowledge of REST APIs, Experience with microservices, Experience with distributed systems, Experience with event-driven architectures, Hands-on experience with Kafka, Experience with asynchronous processing, Experience with AWS, Experience with Kubernetes, Experience with Amazon EKS, Experience with PostgreSQL, Knowledge of CI/CD, Experience with containerization, Knowledge of observability tooling, Knowledge of OAuth2, Knowledge of IAM, English proficiency, Polish proficiency, Availability for hybrid work in Katowice 📃 Skills: Kotlin, Spring, SpringBoot, REST, Microservices, Kafka, AWS, Kubernetes, EKS, PostgreSQL, CI/CD, Docker, OAuth2, IAM 🏢 Description: Responsibilities We are looking for a strong backend engineer who wants to design and scale core systems powering product and assortment management across a large retail ecosystem . You will take ownership of backend architecture and system evolution within the assortment management domain , building scalable services and integrations across a complex, event-driven enterprise landscape. You act as a technical driver within the team, working closely with architects, product owners and stakeholders to deliver robust, high-quality solutions. Your key responsibilities include: Design and develop scalable backend services , APIs and integrations using Kotlin and Spring Boot within distributed systems. Translate complex business and product data requirements into robust , maintainable and scalable system designs . Lead the design and evolution of event - driven architectures and asynchronous processing using Kafka . Design and integrate backend systems within AWS and Kubernetes -based enterprise environments. Drive data modeling and persistence strategies using PostgreSQL and cloud - native approaches. Act as a technical interface between business , product and engineering teams, leading solution design and backlog refinement . Drive engineering best practices , observability , reliability and architectural consistency across the platform. Lead troubleshooting , optimization and continuous improvement initiatives while mentoring less experienced engineers. Benefits Motivizer Benefits Platform to choose and manage all your benefits in one place. You receive a budget (550 PLN monthly). You can choose medical care package, meal tickets, sports cards (we have Multisport and on preferential terms, we have membership cards to one of the most popular Gyms), cinema tickets, shop vouchers, discounts and many more. Language Courses – you'll have access to a multi-language learning platform enabling you to practice your language skills and learn new ones! Regular and systematic further training opportunities - both internally and from external providers. We support your ongoing learning and development. Cooperation within an internal community is our everyday reality. We have networking events, coding challenges, and company parties for different occasions. Qualifications Completed university degree in Computer Science or a comparable technical field. 6+ years of professional experience in backend development using Kotlin and Spring Boot in complex environments. Strong expertise in REST APIs , microservices , distributed systems and event - driven architectures . Deep hands-on experience with Kafka and asynchronous processing patterns in production systems. Strong experience with AWS and Kubernetes (including Amazon EKS ) in scalable environments. Solid experience with PostgreSQL and designing performant, reliable data models. Experience with CI/CD , containerization , observability tooling and modern security concepts (OAuth2, IAM). Strong communication skills in English and Polish , with readiness to work in a hybrid model in Katowice . About OBI Smart Technologies WHO ARE WE: We are a joint venture between OBI and Reply Group, responsible for co-designing, building and operating mission-critical digital platforms for commerce, customer service, and omnichannel retail. OUR MISSION: " We unite technology leadership with deep retail vision to implement standardized processes and scalable digital products that drive efficient support for one of Europe’s largest DIY retailers. Leveraging proven best practices, we advance the internationalization of products and the digital mindset of our partners, delivering consistent and business-critical solutions to support the targets of our customer. "

🏢 Summary: Senior Backend Engineer role for a 3-month modernization project focused on upgrading Java and Scala backend services, migrating authentication systems to OAuth, and building large-scale Spark data pipelines. The position requires hybrid work in Warsaw or Kraków, with a fully covered onboarding period in Sweden. 🗂️ Requirements: 5+ years commercial backend experience, Strong production experience with Java, Strong production experience with Scala, Experience with Play Framework or Akka/Pekko, Hands-on experience with Spark, Experience with OAuth authentication, Professional English proficiency, Availability for 2-week onboarding in Sweden, Hybrid availability in Warsaw or Kraków office 3 days/week 📃 Skills: Java, Scala, Play, Akka, Pekko, Spark, OAuth, React, TypeScript, CI/CD, Gradle 🏢 Description: co.brick talents — powered by AI, powered by people. Senior Backend Engineer (Scala / Java) – 3-Month Project Salary: Up to 175 PLN/h net + VAT (B2B Contract) Location: Hybrid – Warsaw or Kraków ( strictly 3 days/week from the office – non-negotiable) Onboarding: 2 weeks on-site in Malmö, Sweden (fully covered) Project Duration: 3 months Start Date: ASAP/Beginning of August at the ABSOLUTE LATEST About the Client & Project On behalf of our client, an innovative company from the technology sector, we are looking for a Strong Senior Backend Developer to join a short-term, high-impact project. The main goal is to modernize and optimize core backend services, streamline data pipelines, and enhance system security. This is a highly autonomous role requiring a seasoned engineer who can jump straight into a complex ecosystem, utilize automation tools for framework upgrades, and handle heavy data migration tasks. Key Responsibilities Modernize and refactor backend services by upgrading legacy Java and Scala-based frameworks. Leverage automation and modern tooling to expedite code transformations, dependency resolution, and compatibility fixes. Migrate legacy authentication mechanisms across various services to secure, OAuth-based solutions. Consolidate multiple data stores into unified, versioned tables by designing and executing heavy Spark/Java batch pipelines. Requirements Minimum of 5 years of commercial backend experience (7+ years is highly preferred). Deep production experience with Java and Scala . Strong familiarity with Play Framework OR Akka (experience with Akka/Pekko is highly acceptable if you are ready to work with Play environments). Hands-on experience with Spark for complex, heavy data pipeline processing. Solid understanding and practical experience with OAuth authentication patterns. Excellent communication skills with Full Professional English (the project language is 100% English). Full availability for a 2-week onboarding trip to Sweden at the very start of the contract. Nice to Have Basic understanding or exposure to frontend technologies (React / TypeScript). DevOps mindset: familiarity with CI/CD pipelines, Gradle, and scripting. What We Offer A transparent, quick 2-stage recruitment process. An attractive hourly rate with seamless B2B invoicing. An opportunity to work on a high-exposure architectural modernization project for an international client.

🏢 Summary: Senior Backend Engineer role for a 3-month modernization project focused on upgrading Java and Scala backend services, migrating authentication systems to OAuth, and building heavy Spark-based data pipelines. The position requires hybrid work in Warsaw or Kraków with an initial onboarding in Sweden. 🗂️ Requirements: 5+ years commercial backend experience, Production experience with Java, Production experience with Scala, Experience with Play Framework or Akka/Pekko, Hands-on Spark experience, Experience with OAuth authentication, Professional English proficiency, Availability for 2-week onboarding in Sweden, Hybrid availability 3 days/week in Warsaw or Kraków office 📃 Skills: Java, Scala, Play, Akka, Pekko, Spark, OAuth, React, TypeScript, CI/CD, Gradle 🏢 Description: co.brick talents — powered by AI, powered by people. Senior Backend Engineer (Scala / Java) – 3-Month Project Salary: Up to 175 PLN/h net + VAT (B2B Contract) Location: Hybrid – Warsaw or Kraków ( strictly 3 days/week from the office – non-negotiable) Onboarding: 2 weeks on-site in Malmö, Sweden (fully covered) Project Duration: 3 months Start Date: ASAP/Beginning of August at the ABSOLUTE LATEST About the Client & Project On behalf of our client, an innovative company from the technology sector, we are looking for a Strong Senior Backend Developer to join a short-term, high-impact project. The main goal is to modernize and optimize core backend services, streamline data pipelines, and enhance system security. This is a highly autonomous role requiring a seasoned engineer who can jump straight into a complex ecosystem, utilize automation tools for framework upgrades, and handle heavy data migration tasks. Key Responsibilities Modernize and refactor backend services by upgrading legacy Java and Scala-based frameworks. Leverage automation and modern tooling to expedite code transformations, dependency resolution, and compatibility fixes. Migrate legacy authentication mechanisms across various services to secure, OAuth-based solutions. Consolidate multiple data stores into unified, versioned tables by designing and executing heavy Spark/Java batch pipelines. Requirements Minimum of 5 years of commercial backend experience (7+ years is highly preferred). Deep production experience with Java and Scala . Strong familiarity with Play Framework OR Akka (experience with Akka/Pekko is highly acceptable if you are ready to work with Play environments). Hands-on experience with Spark for complex, heavy data pipeline processing. Solid understanding and practical experience with OAuth authentication patterns. Excellent communication skills with Full Professional English (the project language is 100% English). Full availability for a 2-week onboarding trip to Sweden at the very start of the contract. Nice to Have Basic understanding or exposure to frontend technologies (React / TypeScript). DevOps mindset: familiarity with CI/CD pipelines, Gradle, and scripting. What We Offer A transparent, quick 2-stage recruitment process. An attractive hourly rate with seamless B2B invoicing. An opportunity to work on a high-exposure architectural modernization project for an international client.

🏢 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: Senior Backend Engineer role focused on transforming a mission-critical e-commerce domain supporting subscriptions and purchasing journeys for millions of users. The position centers on migrating a monolithic system to scalable microservices, improving performance and reliability, and shaping the future architecture of a global platform. Engineers will work with event-driven systems and modern AI tools while owning solutions end-to-end. 🗂️ Requirements: 5+ years of professional backend engineering experience, Strong experience designing and operating microservices architectures, Experience modernising legacy systems and decomposing monoliths, Solid understanding of distributed systems and scalable backend design, Commercial experience with Go, Java, Kotlin or Scala, Hands-on experience with Kafka or similar event-streaming technologies, Hands-on experience with PostgreSQL, Hands-on experience with Docker and Kubernetes, Experience with CI/CD pipelines, Practical experience using AI coding assistants (Claude Code, Cursor, Copilot or similar), Ability to review and validate AI-generated code, Comfortable owning solutions from idea to production 📃 Skills: Go, Golang, Java, Kotlin, Scala, Kafka, PostgreSQL, Docker, Kubernetes, CI/CD, GraphQL, DDD, TDD, BDD, Microservices 🏢 Description: Join a global e-commerce technology organisation serving millions of customers across multiple international markets. As a Senior Backend Engineer, you will become part of a team responsible for one of the company's most critical customer-facing domains. The platform supports customer subscriptions, plans, and purchasing journeys used daily by millions of users. This is not a maintenance role. The team is actively transforming a mission-critical domain, modernising legacy systems, reducing technical debt, and building the next generation of scalable services that will support future growth. You will play a key role in migrating core functionality from a monolithic architecture to modern microservices while helping shape the future architecture of a global platform. What You'll Do Build & Scale Core Services Design, develop, and maintain scalable backend services within a distributed microservices architecture. Build reliable systems supporting millions of customer interactions. Improve performance, reliability, and scalability across critical customer-facing services. Drive Modernisation Lead the migration of key business domains from monolithic systems to modern microservices. Reduce technical debt and improve long-term maintainability. Design solutions that support future platform growth. Shape Architecture Participate in architecture discussions and technical decision-making. Design orchestration layers supporting complex customer journeys and business processes. Help define engineering standards and best practices. Work with Event-Driven Systems Build and operate services powered by event-driven architectures. Work extensively with Kafka and real-time lifecycle events. Design resilient and observable distributed systems. Raise Engineering Standards Conduct code reviews and support other engineers through technical guidance. Promote best practices across software development, testing, deployment, and observability. Contribute to a strong culture of ownership and continuous improvement. AI-Powered Engineering Use modern AI tools and coding agents throughout the software development lifecycle. Leverage AI for onboarding, architecture exploration, implementation, testing, debugging, and productivity improvements. Apply engineering judgement to validate, verify, and safely integrate AI-generated outputs. What We're Looking For Backend Engineering Expertise 5+ years of professional backend engineering experience. Strong experience designing and operating microservices architectures. Experience modernising legacy systems and decomposing monoliths. Solid understanding of distributed systems and scalable backend design. Technical Stack Commercial experience with Go (Golang), Java, Kotlin or Scala Engineers coming from a JVM background should be open to working in a Go-driven environment. Hands-on experience with: Kafka or similar event-streaming technologies PostgreSQL Docker Kubernetes CI/CD pipelines Product & Ownership Mindset Comfortable owning solutions from idea through production. Strong problem-solving skills and ability to make technical trade-offs. Experience collaborating with product, business, and engineering stakeholders. AI Fluency Practical experience using AI coding assistants such as Claude Code, Cursor, Copilot, or similar tools. Understanding of how context, prompts, constraints, and validation influence AI-generated outputs. Ability to critically review and verify AI-generated solutions. Nice to Have Experience with subscription-based products. Experience in e-commerce environments. GraphQL knowledge. Familiarity with DDD, TDD, and BDD practices. What We Offer Opportunity to build systems used by millions of customers globally. High-impact engineering work with significant architectural ownership. International collaboration across distributed engineering teams. End-to-end ownership from idea to production. Hybrid working model (3 days per week in the Warsaw office). B2B cooperation model. 30 days of paid annual leave. Modern office located in Warsaw city centre. Continuous learning and professional growth opportunities.

🏢 Summary: Senior Backend Engineer role focused on designing and developing scalable, reliable backend services using Java. The position involves working in a cross-functional team to build high-performance systems, improve architecture, and support CI/CD and production environments. 🗂️ Requirements: 5+ years Backend Engineering experience, Strong Java proficiency, Solid knowledge of databases and SQL, Experience with RESTful APIs, Experience with microservices architecture, Experience with high-load systems, Experience with Docker and Kubernetes, Experience with AWS or GCP, Knowledge of CI/CD pipelines, Understanding of Agile practices 📃 Skills: Java, SQL, REST, Microservices, Docker, Kubernetes, AWS, GCP, CI/CD, Golang, Python 🏢 Description: We are looking for a Senior Backend Engineer with strong Java experience to help us design and develop scalable solutions. You will work in a cross-functional team, building reliable services and contributing to the continuous improvement of our systems. This role is ideal for someone who enjoys solving complex problems and driving technical excellence. 💼 Responsibilities: Design, develop, and maintain backend features and services. Collaborate with teams to define requirements and integrate systems. Ensure performance, scalability, and reliability of applications. Contribute to CI/CD processes and support production systems. Write clear documentation and share knowledge within the team. ✅ Requirements: 5+ years of experience as a Backend Engineer, with strong Java skills (Golang/Python is a plus). Solid understanding of databases and SQL. Experience with RESTful API design, microservices, and high-load systems. Familiarity with Docker, Kubernetes, and cloud environments (AWS/GCP). Knowledge of CI/CD pipelines and Agile practices. Strong problem-solving and communication skills. 🎁 We offer: Stable employment in a fast-growing company. Flexible and remote-friendly working model. Health and wellbeing benefits. Learning and development opportunities. Modern equipment and comfortable work environment.

🏢 Summary: Senior Backend Java Developer role focused on designing and building scalable, high-performance backend systems using Java and Spring Boot in a cloud-native environment. The position involves developing enterprise-grade solutions, ensuring performance and security, and supporting containerized deployments. The role requires strong experience with modern backend technologies and infrastructure tools. 🗂️ Requirements: 8+ years of backend development experience, Strong experience with Java 17+, Strong experience with Spring and Spring Boot, Experience with Spring Security, Experience with SQL databases, Experience with Maven, Experience with Git and CI/CD pipelines, Experience with testing frameworks (JUnit, AssertJ, Hamcrest), Experience with Kubernetes and Helm, Experience with Bash or Shell scripting, Experience with cloud-native applications, Experience in enterprise environments 📃 Skills: Java, Spring, SpringBoot, SpringSecurity, SQL, Maven, Git, CICD, JUnit, AssertJ, Hamcrest, Kubernetes, Helm, Bash, Shell, Docker, PostgreSQL 🏢 Description: Senior Backend Java Developer Location: Warsaw, Poland (hybrid – 2 days/week in the office) About the Role We’re looking for a Senior Backend Java Developer to design and build scalable, high-performance backend systems for international products. You’ll work in a collaborative environment, contribute to architectural decisions, and mentor other engineers. Responsibilities Design, develop, and maintain backend systems using Java 17+ and Spring Boot Ensure scalability, performance, and security of solutions Work with SQL databases (e.g. PostgreSQL) Support deployments using Docker, Kubernetes, and Helm Use Bash/Shell for automation and integration tasks Lead technical discussions and mentor team members Collaborate in Agile (Scrum) teams and communicate in English Requirements Strong experience with Java 17+, Spring / Spring Boot / Spring Security Experience with cloud-native applications Maven, SQL, Git (GitHub, CI/CD) Testing frameworks (JUnit, AssertJ, Hamcrest) Kubernetes, Helm Bash/Shell scripting English B2/C1 Experience in enterprise environments 8+ years of backend development experience Nice to Have PostgreSQL, Hibernate/JPA Kafka, event-driven architecture Microservices architecture Python Knowledge of C or Go CI/CD tools, JIRA Monitoring tools (Grafana, Prometheus, Kibana) Security best practices (OWASP) Qualifications Degree in Computer Science or related field

🏢 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.