Senior Java Developer

🏢 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 Java Developer contract for a logistics project, focused on building secure, high-performance backend data-processing services in a microservices architecture. The role uses Java, Confluent Kafka/KStreams, MongoDB Atlas and PostgreSQL, with hybrid work from the Warsaw office 2–3 days per week. 🗂️ Requirements: 10+ years of Java development experience, Strong Confluent Kafka expertise, Strong KStreams expertise, MongoDB Atlas experience, PostgreSQL experience, English proficiency, Polish proficiency 📃 Skills: Java, Kafka, Confluent, KStreams, MongoDB, PostgreSQL, CI/CD, Microservices 🏢 Description: Work model: 2–3 days a week from the Warsaw office Rate: B2B, up to 190 zł/h Start: ASAP or within 1 month Project length: More than 12 months, with extensions Project language: English and Polish Industry: Logistics Recruitment process: 2 interviews with the client Workload: Full-time Summary The Senior Java Developer is primarily responsible for designing and developing backend applications while ensuring high standards of security, performance, and quality. The role focuses on leveraging extensive Java and Kafka experience to build robust data-processing solutions within a microservices architecture. Main Responsibilities - Build, test, and deploy software using CI/CD pipelines. - Create microservices for data processing, database interactions, and data exposure. - Implement relevant architectural patterns for data handling and web services. - Ensure accurate logging and alert configurations for operational efficiency. - Conduct comprehensive software testing against various performance criteria. - Integrate security features, including authentication and authorization controls. - Participate in a developer guild to share best practices and technical knowledge. Key Requirements - 10+ years of relevant Java development experience. - Strong Kafka expertise, particularly Confluent Kafka and KStreams. - Experience with MongoDB Atlas and PostgreSQL. Nice to Have - Familiarity with OIDC, OAuth2, and SAML authentication protocols. - Experience with Docker containerization. - Knowledge of Kubernetes container orchestration. - Experience with the ELK stack for logging, monitoring, and alerting.

🏢 Summary: Backend Developer role focused on modernizing and optimizing backend services and data pipelines, including migration to newer Java/Scala and Play Framework versions and implementation of OAuth-based authentication. The position involves automation with GenAI tools and Spark-based data migrations in a hybrid work model. B2B contract with onboarding in Sweden and full-time engagement in English. 🗂️ Requirements: Hands-on experience with production Java services, Hands-on experience with production Scala services, Experience with Play Framework internals, Experience with Spark for pipeline-heavy work, Experience with OAuth-based authentication patterns, Availability to work hybrid from Warsaw or Cracow office, Availability for 2-week onboarding in Malmo, Sweden, Fluency in English 📃 Skills: Java, Scala, Play, Spark, OAuth, JDK, GenAI, Gradle, CI/CD, React, TypeScript 🏢 Description: 🌍 Work mode: hybrid –  3 days from the Warsaw OR Cracow office. ⏳ Duration : > 3 months contracts . 🔍 Onboarding : 2 weeks in Malmo, Sweden. ⏰ Start : August 3rd at the latest. 📝 Contract : B2B > up 195 zl/h. ⚙️ Recruitment process : 2 meetings. 📕Project language : English. 💼 Industry : Technology. 💻 Workload : Full time (40 hours per week). Summary: The Backend Developer role is aimed at enhancing and modernizing backend services and pipelines within the organization. This position primarily focuses on improving system performance, ensuring robust authentication mechanisms, and implementing automation to streamline processes. Main Responsibilities: Modernise backend services and pipelines by upgrading to the latest JDK, Scala 3.x, and Play Framework 3.x. Apply GenAI tooling to automate code transformations, dependency resolution, and compatibility fixes, producing reusable tools and documentation. Migrate authentication frameworks from legacy APIs to OAuth-based solutions across various backend services. Replace multiple data stores with a single versioned table, creating Spark/Java batch pipelines for backfill/migration and extending Scala/Play backends. Key Requirements: Hands-on experience with production Java/Scala services . Familiarity with Play Framework internals. Experience with Spark for pipeline-heavy work. Comfortable with OAuth-based authentication patterns. Nice to Have: Familiarity with React/TypeScript. For DevOps-leaning candidates: experience with Gradle, scripting, and CI/CD pipelines. Other Details: Tools/Methodologies: Java, Scala, Play Framework, Spark, OAuth.

🏢 Summary: Full-time hybrid Backend Developer contract focused on modernizing backend services, migrating authentication systems to OAuth, and building Spark-based data migration pipelines. The role involves upgrading Java/Scala ecosystems, automating transformations with GenAI tooling, and extending Scala/Play Framework backends in an English-speaking international environment. 🗂️ Requirements: Production experience with Java, Production experience with Scala, Knowledge of Play Framework internals, Experience with Spark, Knowledge of OAuth authentication patterns, Availability for hybrid work in Krakow, English proficiency 📃 Skills: Java, Scala, Play, Spark, OAuth, GenAI, React, TypeScript, Gradle, CI/CD 🏢 Description: Industry: Technology solutions - consumer electronics, software, streaming Client: global enterprise, Swedish entity Work model: full time, hybrid 3 days/week on-site fromKrakow (Equal Business Park) office Project language: English Onboarding : 3 days in Malmo, Sweden Start: ASAP or 1 week notice ideally / at latest start 27th July 2026 Assignment type: B2B Remuneration: up to 200 PLN/h net + VAT FTE: full-time Summary: The Backend Developer role is aimed at enhancing and modernizing backend services and pipelines within the organization. This position primarily focuses on improving system performance, ensuring robust authentication mechanisms, and implementing automation to streamline processes. Main Responsibilities: Modernise backend services and pipelines by upgrading to the latest JDK, Scala 3.x, and Play Framework 3.x. Apply GenAI tooling to automate code transformations, dependency resolution, and compatibility fixes, producing reusable tools and documentation. Migrate authentication frameworks from legacy APIs to OAuth-based solutions across various backend services. Replace multiple data stores with a single versioned table, creating Spark/Java batch pipelines for backfill/migration and extending Scala/Play backends. Key Requirements: Hands-on experience with production Java/Scala services . Familiarity with Play Framework internals or Akka. Experience with Spark for pipeline-heavy work. Comfortable with OAuth-based authentication patterns. Nice to Have: Familiarity with React/TypeScript. For DevOps-leaning candidates: experience with Gradle, scripting, and CI/CD pipelines.

🏢 Summary: Backend Developer role focused on modernizing and optimizing backend services and data pipelines, including technology upgrades, authentication migration, and automation initiatives. The position involves working with Java/Scala ecosystems, Spark pipelines, and OAuth-based security in a hybrid model with onboarding in Sweden. B2B contract with competitive hourly rate and English as the project language. 🗂️ Requirements: Hands-on experience with production Java services, Hands-on experience with production Scala services, Familiarity with Play Framework internals, Experience with Spark for data pipelines, Experience with OAuth-based authentication patterns, Availability for hybrid work (3 days/week in Warsaw or Cracow), Availability for 2-week onboarding in Malmo, Sweden, Fluent English 📃 Skills: Java, Scala, Play, Spark, OAuth, Gradle, CI/CD, React, TypeScript 🏢 Description: 🌍 Work mode: hybrid –  3 days from the Warsaw OR Cracow office. ⏳ Duration : > 3 months contracts . 🔍 Onboarding : 2 weeks in Malmo, Sweden. ⏰ Start : August 3rd at the latest. 📝 Contract : B2B > up 200 zl/h. ⚙️ Recruitment process : 2 meetings. 📕Project language : English. 💼 Industry : Technology. 💻 Workload : Full time (40 hours per week). Summary: The Backend Developer role is aimed at enhancing and modernizing backend services and pipelines within the organization. This position primarily focuses on improving system performance, ensuring robust authentication mechanisms, and implementing automation to streamline processes. Main Responsibilities: Modernise backend services and pipelines by upgrading to the latest JDK, Scala 3.x, and Play Framework 3.x. Apply GenAI tooling to automate code transformations, dependency resolution, and compatibility fixes, producing reusable tools and documentation. Migrate authentication frameworks from legacy APIs to OAuth-based solutions across various backend services. Replace multiple data stores with a single versioned table, creating Spark/Java batch pipelines for backfill/migration and extending Scala/Play backends. Key Requirements: Hands-on experience with production Java/Scala services . Familiarity with Play Framework internals. Experience with Spark for pipeline-heavy work. Comfortable with OAuth-based authentication patterns. Nice to Have: Familiarity with React/TypeScript. For DevOps-leaning candidates: experience with Gradle, scripting, and CI/CD pipelines. Other Details Tools/Methodologies: Java, Scala, Play Framework, Spark, OAuth.

🏢 Summary: Hybrid Backend Developer role focused on modernizing and optimizing backend services, upgrading core technologies, and improving authentication and data pipelines. The project involves Java/Scala development, Play Framework upgrades, Spark-based batch processing, and OAuth migration. B2B contract with fast recruitment process and onboarding in Sweden. 🗂️ Requirements: Hands-on experience with production Java services, Hands-on experience with production Scala services, Familiarity with Play Framework internals, Experience with Spark for pipeline-heavy work, Experience with OAuth-based authentication patterns, Fluent English for project communication 📃 Skills: Java, Scala, Play, Spark, OAuth, JDK, GenAI, Gradle, CI/CD, React, TypeScript 🏢 Description: 🌍 Work mode: hybrid –  3 days from the Warsaw office. 🔍 Onboarding : 2 weeks in Malmo, Sweden. ⏰ Start : 1 week notice period, August 3rd at the latest. 📝 Contract : B2B > up 195 zl/h. ⚙️ Recruitment process : 1 meeting with the client. ⏳ Duration : > 3 months contracts + extensions. 📕Project language : English. 💼 Industry : Technology. 💻 Workload : Full time (40 hours per week). Summary: The Backend Developer role is aimed at enhancing and modernizing backend services and pipelines within the organization. This position primarily focuses on improving system performance, ensuring robust authentication mechanisms, and implementing automation to streamline processes. Main Responsibilities: Modernise backend services and pipelines by upgrading to the latest JDK, Scala 3.x, and Play Framework 3.x. Apply GenAI tooling to automate code transformations, dependency resolution, and compatibility fixes, producing reusable tools and documentation. Migrate authentication frameworks from legacy APIs to OAuth-based solutions across various backend services. Replace multiple data stores with a single versioned table, creating Spark/Java batch pipelines for backfill/migration and extending Scala/Play backends. Key Requirements: Hands-on experience with production Java/Scala services . Familiarity with Play Framework internals. Experience with Spark for pipeline-heavy work. Comfortable with OAuth-based authentication patterns. Nice to Have: Familiarity with React/TypeScript. For DevOps-leaning candidates: experience with Gradle, scripting, and CI/CD pipelines. Other Details Tools/Methodologies: Java, Scala, Play Framework, Spark, OAuth.

🏢 Summary: Full-time B2B contract for a Senior Backend Test Automation Engineer focused on backend microservices and distributed data platforms in the consumer electronics and streaming industry. The role involves integration testing, ETL and data pipeline validation, and automated test execution in JVM-based backend environments. Hybrid work model with 3 days onsite in Krakow and onboarding in Malmö. 🗂️ Requirements: Strong experience testing backend microservices, Hands-on experience with integration testing across distributed systems, Experience with Play Framework or JVM-based backend services in Java/Scala, Understanding of Apache Spark and testing data pipelines, Experience validating ETL and data processing workflows, Ability to manage test data and deterministic test environments, Experience with CI/CD and automated test execution, Ability to debug failures across services, databases, queues, and pipelines, English proficiency 📃 Skills: Java, Scala, Play, Akka, Spark, SQL, ScalaTest, JUnit, Testcontainers, Docker, Kubernetes, GitHub, Jenkins, Azure 🏢 Description: Senior Backend Test Automation Engineer with strong data platform experience Industry: Technology solutions - consumer electronics, software, streaming Client: global enterprise, Swedish entity Work model: full time, hybrid 3 days/week on-site from Krakow (Equal Business Park) office Project language: English Onboarding : 3 days in Malmo, Sweden Start: ASAP or 1 week notice ideally / at latest start 27th July 2026 Assignment type: B2B Remuneration: up to 195 PLN/h net + VAT FTE: full-time Strong experience testing backend microservices rather than web UIs. Hands-on experience with integration testing across distributed systems. Experience with Play Framework (or at least JVM-based backend services in Java/Scala). Good understanding of Apache Spark and testing data pipelines. Experience validating ETL/data processing workflows. Comfortable managing test data, data dependencies, and deterministic test environments. Experience with CI/CD and automated test execution. Ability to debug failures across multiple services, databases, queues, and pipelines. Likely technical stack includes: Java and/or Scala Play Framework or Akka Apache Spark SQL Integration test frameworks (ScalaTest, JUnit, Testcontainers, etc.) Docker/Kubernetes GitHub Actions, Jenkins, Azure DevOps, or similar

🏢 Summary: Full-time B2B role for a Senior Backend Test Automation Engineer focused on testing backend microservices and distributed data platforms in a hybrid model from Krakow. The position involves integration testing, validating ETL and data processing workflows, and working with JVM-based backend services using Java or Scala. The project requires strong experience with CI/CD, automated testing, and debugging across distributed systems. 🗂️ Requirements: Strong experience testing backend microservices, Experience with integration testing across distributed systems, Experience with Play Framework or JVM-based backend services in Java/Scala, Good understanding of Apache Spark, Experience testing ETL and data processing workflows, Ability to manage test data and deterministic test environments, Experience with CI/CD and automated test execution, Ability to debug failures across services, databases, queues, and pipelines, English proficiency, Availability for hybrid work in Krakow 📃 Skills: Java, Scala, Play, Spark, SQL, ScalaTest, JUnit, Testcontainers, Docker, Kubernetes, GitHub, Jenkins, Azure, CI/CD, ETL 🏢 Description: Senior Backend Test Automation Engineer with strong data platform experience Industry: Technology solutions - consumer electronics, software, streaming Client: global enterprise, Swedish entity Work model: full time, hybrid 3 days/week on-site from Krakow (Equal Business Park) office Project language: English Onboarding : 3 days in Malmo, Sweden Start: ASAP or 1 week notice ideally / at latest start 27th July 2026 Assignment type: B2B Remuneration: up to 195 PLN/h net + VAT FTE: full-time Strong experience testing backend microservices rather than web UIs. Hands-on experience with integration testing across distributed systems. Experience with Play Framework (or at least JVM-based backend services in Java/Scala). Good understanding of Apache Spark and testing data pipelines. Experience validating ETL/data processing workflows. Comfortable managing test data, data dependencies, and deterministic test environments. Experience with CI/CD and automated test execution. Ability to debug failures across multiple services, databases, queues, and pipelines. Likely technical stack includes: Java and/or Scala Play Framework Apache Spark SQL Integration test frameworks (ScalaTest, JUnit, Testcontainers, etc.) Docker/Kubernetes GitHub Actions, Jenkins, Azure DevOps, or similar

🏢 Summary: Full-time B2B contract for a Senior Backend Test Automation Engineer focused on testing backend microservices, distributed systems, and data platforms in a hybrid model from Krakow. The role involves integration testing, ETL and data pipeline validation, CI/CD automation, and debugging across complex backend environments using Java/Scala technologies. Onboarding includes a short stay in Malmö, with an immediate or near-immediate start preferred. 🗂️ Requirements: Strong experience testing backend microservices, Hands-on experience with integration testing across distributed systems, Experience with Play Framework, Experience with JVM-based backend services, Understanding of Apache Spark, Experience testing data pipelines, Experience validating ETL workflows, Ability to manage test data and deterministic test environments, Experience with CI/CD and automated test execution, Ability to debug failures across services, databases, queues, and pipelines, English proficiency 📃 Skills: Java, Scala, Play, Spark, SQL, ScalaTest, JUnit, Testcontainers, Docker, Kubernetes, GitHub, Jenkins, Azure, CI/CD, ETL 🏢 Description: Senior Backend Test Automation Engineer with strong data platform experience Industry: Technology solutions - consumer electronics, software, streaming Client: global enterprise, Swedish entity Work model: full time, hybrid 3 days/week on-site from Krakow (Equal Business Park) office Project language: English Onboarding : 3 days in Malmo, Sweden Start: ASAP or 1 week notice ideally / at latest start 27th July 2026 Assignment type: B2B Remuneration: up to 195 PLN/h net + VAT FTE: full-time Strong experience testing backend microservices rather than web UIs. Hands-on experience with integration testing across distributed systems. Experience with Play Framework (or at least JVM-based backend services in Java/Scala). Good understanding of Apache Spark and testing data pipelines. Experience validating ETL/data processing workflows. Comfortable managing test data, data dependencies, and deterministic test environments. Experience with CI/CD and automated test execution. Ability to debug failures across multiple services, databases, queues, and pipelines. Likely technical stack includes: Java and/or Scala Play Framework Apache Spark SQL Integration test frameworks (ScalaTest, JUnit, Testcontainers, etc.) Docker/Kubernetes GitHub Actions, Jenkins, Azure DevOps, or similar

🏢 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