Kafka Expert (Staff/Principal)

🏢 Summary: Remote-first Scala Developer role focused on building scalable and maintainable systems using functional programming and modern JVM technologies. The offer includes flexible cooperation, strong engineering culture, and work on projects involving distributed systems, Big Data, and Blockchain. Candidates will design and develop high-quality software in small, technically driven teams. 🗂️ Requirements: Very good Scala skills, Strong functional programming knowledge, Ability to write clean and testable code, Minimum 4 years of commercial software development experience, Understanding of software architecture patterns, Ability to design scalable and maintainable systems, Knowledge of industry trends, Team collaboration skills, Very good English (spoken and written), Polish language proficiency 📃 Skills: Scala, Akka, Zio, Cats, Slick, Blockchain, Cassandra, MongoDB, Kafka, JVM 🏢 Description: Our cooperation offer: Remuneration ranging from 125 to 185 PLN net per hour for start 100% remote company with a remote-first mindset Flexible cooperation from any location and without strict schedule Professional development and freedom in choosing the toolset and tech stack Learning-culture expressed by in-house trainings, technical and soft-skills reading clubs and Architecture club Access to many AI tools (Claude, OpenAI, Cursor, Gemini, Copilot, etc.) Leadership and soft-skills in-house trainings English courses Small to medium teams with as little procedures as possible Best tools you need to make our cooperation effective and pleasurable: monitor(s), computer of your choice Dev-friendly environment with passionate and skilled people who believe in clean code and software craftsmanship - you will have a chance to meet some of them during the selection process Interesting projects with technologies like Scala, Akka, Zio, Cats, Slick, Blockchain, Cassandra, MongoDB, Apache Kafka What we expect: Very good Scala skills and functional programming knowledge Ability to write clean and testable code At least 4 years of commercial experience in developing software Understanding of different types of software architecture Ability to design with scalability and maintainability in mind Comprehensive knowledge and understanding of the industry trends Team collaboration ability Good knowledge of English is a must (both spoken and written), we cooperate with clients from all over the world (USA, Australia, Switzerland, etc.) Polish language is required, as internally we are a Polish speaking company Nice to have: Actor model and Akka / Pekko Knowledge of a second JVM language Experience in using AI in software development and deployment cycle Engagement in the IT community: personal blog, speaking at meetups/conferences, involvement in the open-source projects Having a pet-project Interest in Big Data, Machine Learning and/or Blockchain

🏢 Summary: Junior-level role in a project building a high-performance, scalable messaging platform for financial institutions, focused on message transport, transformation, routing, and monitoring in a critical environment. The position offers hands-on experience with enterprise financial systems and development toward Java backend or DevOps paths. Work is in a hybrid model with on-call support in a time-sensitive setup. 🗂️ Requirements: Basic experience in Java, Interest in DevOps, Good command of English (spoken and written), Availability for on-call support (rotational shifts), Ability to work in time-sensitive environments, Problem-solving skills, Willingness to work on-site 2 days per week 📃 Skills: Java, Spring, SpringBoot, Kubernetes, OpenShift, Docker, ActiveMQ, IBMMQ, Elasticsearch, PostgreSQL, DB2, ArgoCD, GitOps, Incentage 🏢 Description: Salary: 252 - 350 PLN/ day net + vat (B2B/Civil contract) Remote: elastic hybrid from our office in Gdynia/Gdańsk (2 days per week on-site) Why choose this offer? International working environment High level of autonomy and collaboration within the team Scandinavian organizational culture supporting real work-life balance Opportunity to learn how financial products and markets operate Project You’ll join a project focused on building a robust, scalable, high-performance messaging platform for financial institutions. The system handles message transport, data transformation, routing, validation, sequencing, and monitoring. It’s a critical, high-throughput environment where reliability matters and attention to detail makes a real impact. Expected competences and knowledge Junior level with strong learning mindset): Basic experience in Java (commercial or solid personal projects) Interest in DevOps, with an eagerness to learn Good command of spoken and written English Problem-solving mindset and ability to react quickly to issues Responsibility and readiness to work in time-sensitive environments Openness to collaboration and knowledge sharing (tech + business teams) Availability for on-call support (morning/evening shifts on rotation) Nice to have: Spring Boot Kubernetes / OpenShift Docker Messaging systems (Apache ActiveMQ, IBM MQ) Elasticsearch Databases (PostgreSQL, DB2) GitOps (ArgoCD) Experience with low-code platforms (e.g., Incentage IMS) What you gain: Exposure to real-world, large-scale financial systems Fast learning curve in a complex enterprise environment Supportive team that helps you grow (no “figure it out alone” culture) Development path toward Java backend / DevOps / Site Reliability Engineer Technologies you'll work with Spring Boot Kubernetes / OpenShift Docker Messaging systems (Apache ActiveMQ, IBM MQ) Elasticsearch Databases (PostgreSQL, DB2) GitOps (ArgoCD) Low-code platforms (e.g., Incentage IMS) Client – why choose this particular client from the Jit portfolio? Jit Team is proud to partner with one of the leading European financial groups responsible for the registration, ownership records, and financial settlement of securities traded on financial markets in Norway and recently extended to other European markets. Jit Team has been a strategic partner to our client in the area of software development since 2017 . Over the course of the partnership, Jit Team's dedicated team working for our client has grown from three to over 30 people , who have worked on the modernization of legacy applications, the implementation of new systems, and the development of a private cloud-based platform to host a variety of financial systems . About Jit Team The Human factor of IT - it's not just a slogan, it's a philosophy. The foundation of Jit Team is people, which is why we prioritise you. We employ over 700 experienced experts . We create highly specialised teams for clients from all over the world. We offer team members developmental projects, a wide range of benefits and a proprietary professional development programme. Behind our maxim are also charitable and educational activities. We support pupils and students by donating learning equipment. We offer internships to help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We are a Polish company and we share what we have achieved over 15 years of activity . By supporting indigenous initiatives, we ensure the circulation of good energy.

🏢 Summary: Backend Engineer role in the Advertising team focused on building and operating high-availability, large-scale microservices and ML-powered systems. The position involves designing and optimizing distributed systems using a modern cloud-native stack (Kotlin, Spring, Kafka, Kubernetes) and integrating big data and machine learning components into a real-time marketplace. The offer includes hybrid work, competitive salary, annual bonus, and strong ownership within an autonomous agile team. 🗂️ Requirements: Proficiency in Kotlin or Java, Willingness to work with Kotlin in greenfield projects, Experience with backend development and microservices, Ability to design and optimize high-performance, distributed systems, Experience with cloud-native technologies, Understanding of data processing and system integration, English proficiency at B2 level or higher 📃 Skills: Kotlin, Java, Spring, Kafka, Kubernetes, BigQuery, Spark, Docker, Consul, GitHub, GitHubActions, MachineLearning, Microservices 🏢 Description: Important things for you Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 10:00 a.m. We also have 30 days of occasional remote work. The salary range for this position depending on the skill set is as follows (contract of employment, tax-deductible cost): PLN 11 200 - 15 250 Annual bonus based on your annual performance and company results. Our team is based in Poznań. About the job Massive Scale : Design, build, and optimize systems that handle thousands of requests per minute. This is high-availability, high-performance engineering in practice. Modern Tech Stack : Work with a world-class, cloud-native environment. Our core technologies include Kotlin, Spring, Kafka, and Kubernetes. We're not shy when it comes to ML too :) True Ownership & Autonomy : We live by a "you build it, you run it" philosophy. You'll join an agile, autonomous team with full ownership of your microservices, from design to deployment. Complex Challenges : From distributed systems and data streaming to algorithmic optimization, you'll tackle the complex backend problems that power a massive, real-time marketplace. End-to-End ML Systems: Bridge the gap between big data and real-time product impact. You’ll build the infrastructure for serving ML models , using BigQuery and Apache Spark for offline data processing. You’ll integrate these components with our microservices architecture to create the sophisticated advertising system that powers a personalized user experience. Join the Advertising team! You will have a chance to build Allegro Ads - one of the most visible products on the platform. Your team works closely with the Machine Learning team, creating the best experience for customers. High performance, engineering best practices and great atmosphere in the team guaranteed! We are looking for people who: Code in Kotlin or Java and are eager to master Kotlin by taking part greenfield project Want to be proud of the code they create ; they value high-quality code reviews and engage in substantive discussions on software engineering best practices; Are excited about building new products and want to experience the journey of launching a fresh project within the Allegro ecosystem; Are open to developing soft skills and embracing a growth mindset through active participation in code reviews, pair programming, and team retrospectives.; Are open to incorporating AI coding assistants into their daily work to maximize efficiency and focus on complex problem-solving Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; Know English at at least B2 level. What's in it for you: Well-located offices (with e.g. fully equipped kitchens, bicycle parking, terraces full of greenery) and excellent work tools (e.g., raised desks, ergonomic chairs, interactive conference rooms). A 16" or 14" MacBook Pro or corresponding Dell with Windows (if you don't like Macs) and all the necessary accessories. A wide selection of fringe benefits in a cafeteria plan - you choose what you like (e.g., medical, sports or lunch packages, insurance, purchase vouchers). English classes that we pay for related to the specific nature of your job. A training budget, inter-team tourism ( see more here ), hackathons, and an internal learning platform where you will find multiple trainings. An additional day off for volunteering, which you can use alone, with a team, or with a larger group of people connected by a common goal. Social events for Allegro people - Spin Kilometers, Family Day, Fat Thursday, Advent of Code, and many other occasions we enjoy. And that's just the beginning! You can read more about the benefits here . #goodtobehere means that: You will join a team you can count on - we work with top-class specialists who have knowledge- and experience-sharing in their DNA. You will love our level of autonomy in team organization, the space for continuous development, and the opportunity to try new things. You get to choose which technology solves the problem and you are responsible for what you create. You will value our Developer Experience and the full platform of tools and technologies that make creating software easier. We rely on an internal ecosystem based on self-service and widely used tools such as Kubernetes, Docker, Consul, GitHub, and GitHub Actions. Thanks to this, you can contribute to Allegro from your very first days on the job. You will be equipped with modern AI tools to automate repetitive tasks, allowing you to focus on developing new services and refining existing ones (also leveraging AI support). You will create solutions that will be used (and loved!) by your friends, family and millions of our customers. You will meet the Allegro Scale , which starts with over 1000 microservices, an open-source data bus (Hermes) with 300K+ rps, a Service Mesh with 1M+ rps, tens of petabytes of data, and production-used machine learning. You will become part of Allegro Tech - We speak at industry conferences, cooperate with tech communities, run our own blog (it's been over 10 years!), record podcasts, lead guilds, and we organize our own internal conference - the Allegro Tech Meeting. We create solutions we love (and can) to talk about! Send us your CV and… see you at Allegro!

🏢 Summary: Remote B2B role focused on building and expanding a large-scale analytical and operational data ecosystem delivering campaign performance insights and investment decision support. The position involves developing high-throughput data pipelines, reporting engines, and attribution systems using a modern cloud-based stack. You will work on production-grade data models and scalable systems supporting millions of users. 🗂️ Requirements: Minimum 3 years commercial experience with Java or Kotlin or Scala, Experience with distributed data pipelines, Experience with data processing and analytics systems, Knowledge of GCP cloud environment, Experience with large-scale data systems, Understanding of microservices architecture, Understanding of event-driven systems, Knowledge of data modeling, Willingness to participate in on-call duties, Availability for monthly visits to Warsaw 📃 Skills: Java, Kotlin, Scala, GCP, BigQuery, PostgreSQL, Airflow, Composer, Spark, Spring, Kafka, Microservices, Avro, Terraform, Analytics, DataModeling 🏢 Description: Salary: 600-960 pln/md on B2B Work mode: Remote (with visits to Warsaw once a month and w illingness to participate in on-call duties) Why choose this offer? Work on a high-impact data ecosystem Exposure to large-scale data processing , advanced analytics, and production-grade data models Modern tech stack (GCP, Spark, Airflow, Kafka, microservices) Project Development and expansion of an advanced analytical and operational ecosystem . The project focuses on delivering precise campaign performance data (Insights & Performance) and building tools that support large-scale investment decision-making. It includes creating reliable reporting systems, data attribution models, and scalable data pipelines, ensuring high-quality data availability for professional users. Expected competences and knowledge At least 3 years of commercial experience with Java / Kotlin / Scala Solid understanding of data processing and analytics systems Experience with distributed data pipelines and orchestration tools Knowledge of GCP cloud environment Experience working with large-scale data systems (e.g. BigQuery, Spark) Familiarity with microservices architecture and event-driven systems Understanding of data modeling and data productionization Nice to have Knowledge of Apache ecosystem, Avro, Terraform Responsibilities you’ll have Designing and developing reporting engines and attribution systems (Insights & Performance) Building and maintaining high-throughput data pipelines Collaborating with Data Science teams to productionize advanced data models Ensuring scalability, reliability, and performance of data systems Developing internal tools (bulk management, agency panels, RBAC systems) Supporting complex account structures and permissions management Willingness to participate in on-call duties Technologies you'll work with Java / Kotlin / Scala GCP (BigQuery) PostgreSQL Apache Airflow / Composer Apache Spark Spring Boot Kafka Microservices architecture Apache, Avro, Terraform Client – why choose this particular client from the Jit portfolio? Our Client dominates the Polish e-commerce arena as the market leader since 1999 . With a user base of over 20 million and growing, this well-established platform is at the forefront of e-commerce, constantly striving for growth through market expansion and investment. As a major player in technology, our Client boasts a talented IT team of over 1,000 employees who focus on developing their own cutting-edge technologies. Jit Team has had a successful partnership with our Client since spring 2021 , with multiple software development teams dedicated to our Client's platforms. These teams operate autonomously, designing platform components through micro-services. Working with our Client offers a chance to contribute to a solution used by millions on a daily basis and to tackle the challenge of delivering software at a massive scale , where even a single second of delay can have a significant impact. This project provides a unique opportunity to work with state-of-the-art technologies and tools, making it a rare and valuable experience. About Jit Team The Human factor of IT - it's not just a slogan, it's a philosophy. The foundation of Jit Team is people, which is why we prioritise you. We employ over 700 experienced experts . We create highly specialised teams for clients from all over the world. We offer team members developmental projects, a wide range of benefits and a proprietary professional development programme. Behind our maxim are also charitable and educational activities. We support pupils and students by donating learning equipment. We offer internships to help launch careers in IT. We support water rescuers and hospitals by providing the necessary equipment. We are a Polish company and we share what we have achieved over 15 years of activity . By supporting indigenous initiatives, we ensure the circulation of good energy.

🏢 Summary: Backend engineering role focused on building and operating high‑availability, large‑scale advertising systems in a cloud‑native environment. The position involves designing microservices, integrating ML infrastructure, and processing real‑time and offline data using modern technologies. You will own services end‑to‑end in a distributed, high‑performance ecosystem. 🗂️ Requirements: Proficiency in Kotlin or Java, Experience building microservices, Experience with distributed systems, Experience with high‑performance and high‑availability systems, Experience with data streaming systems, Experience with cloud‑native architectures, Experience integrating ML models into backend systems, Experience with BigQuery and Apache Spark, Ability to work with Kubernetes-based environments, English level B2 or higher 📃 Skills: Kotlin, Java, Spring, Kafka, Kubernetes, Docker, Consul, GitHub, GitHubActions, BigQuery, Spark, Microservices, ML, Hermes 🏢 Description: Important things for you Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 10:00 a.m. We also have 30 days of occasional remote work. The salary range for this position depending on the skill set is as follows (contract of employment, tax-deductible cost): PLN 11 200 - 15 250 Annual bonus based on your annual performance and company results. Our team is based in Poznań. About the job Massive Scale : Design, build, and optimize systems that handle thousands of requests per minute. This is high-availability, high-performance engineering in practice. Modern Tech Stack : Work with a world-class, cloud-native environment. Our core technologies include Kotlin, Spring, Kafka, and Kubernetes. We're not shy when it comes to ML too :) True Ownership & Autonomy : We live by a "you build it, you run it" philosophy. You'll join an agile, autonomous team with full ownership of your microservices, from design to deployment. Complex Challenges : From distributed systems and data streaming to algorithmic optimization, you'll tackle the complex backend problems that power a massive, real-time marketplace. End-to-End ML Systems: Bridge the gap between big data and real-time product impact. You’ll build the infrastructure for serving ML models , using BigQuery and Apache Spark for offline data processing. You’ll integrate these components with our microservices architecture to create the sophisticated advertising system that powers a personalized user experience. Join the Advertising team! You will have a chance to build Allegro Ads - one of the most visible products on the platform. Your team works closely with the Machine Learning team, creating the best experience for customers. High performance, engineering best practices and great atmosphere in the team guaranteed! We are looking for people who: Code in Kotlin or Java and are eager to master Kotlin by taking part greenfield project Want to be proud of the code they create ; they value high-quality code reviews and engage in substantive discussions on software engineering best practices; Are excited about building new products and want to experience the journey of launching a fresh project within the Allegro ecosystem; Are open to developing soft skills and embracing a growth mindset through active participation in code reviews, pair programming, and team retrospectives.; Are open to incorporating AI coding assistants into their daily work to maximize efficiency and focus on complex problem-solving Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; Know English at at least B2 level. What's in it for you: Well-located offices (with e.g. fully equipped kitchens, bicycle parking, terraces full of greenery) and excellent work tools (e.g., raised desks, ergonomic chairs, interactive conference rooms). A 16" or 14" MacBook Pro or corresponding Dell with Windows (if you don't like Macs) and all the necessary accessories. A wide selection of fringe benefits in a cafeteria plan - you choose what you like (e.g., medical, sports or lunch packages, insurance, purchase vouchers). English classes that we pay for related to the specific nature of your job. A training budget, inter-team tourism ( see more here ), hackathons, and an internal learning platform where you will find multiple trainings. An additional day off for volunteering, which you can use alone, with a team, or with a larger group of people connected by a common goal. Social events for Allegro people - Spin Kilometers, Family Day, Fat Thursday, Advent of Code, and many other occasions we enjoy. And that's just the beginning! You can read more about the benefits here . #goodtobehere means that: You will join a team you can count on - we work with top-class specialists who have knowledge- and experience-sharing in their DNA. You will love our level of autonomy in team organization, the space for continuous development, and the opportunity to try new things. You get to choose which technology solves the problem and you are responsible for what you create. You will value our Developer Experience and the full platform of tools and technologies that make creating software easier. We rely on an internal ecosystem based on self-service and widely used tools such as Kubernetes, Docker, Consul, GitHub, and GitHub Actions. Thanks to this, you can contribute to Allegro from your very first days on the job. You will be equipped with modern AI tools to automate repetitive tasks, allowing you to focus on developing new services and refining existing ones (also leveraging AI support). You will create solutions that will be used (and loved!) by your friends, family and millions of our customers. You will meet the Allegro Scale , which starts with over 1000 microservices, an open-source data bus (Hermes) with 300K+ rps, a Service Mesh with 1M+ rps, tens of petabytes of data, and production-used machine learning. You will become part of Allegro Tech - We speak at industry conferences, cooperate with tech communities, run our own blog (it's been over 10 years!), record podcasts, lead guilds, and we organize our own internal conference - the Allegro Tech Meeting. We create solutions we love (and can) to talk about! Send us your CV and… see you at Allegro!

🏢 Summary: Backend engineering role in the Advertising team focused on building and operating high-performance, cloud-native microservices and ML infrastructure at massive scale. The position involves designing distributed systems, data streaming solutions, and end-to-end ML serving pipelines in a real-time marketplace environment. Engineers own services end-to-end, from design to deployment, within a modern Kotlin-based tech stack. 🗂️ Requirements: Proficiency in Kotlin or Java, Experience building high-performance, high-availability backend systems, Experience with distributed systems and microservices architecture, Experience with data streaming systems, Experience with cloud-native environments, Ability to design and deploy ML serving infrastructure, English at B2 level or higher 📃 Skills: Kotlin, Java, Spring, Kafka, Kubernetes, BigQuery, Spark, Docker, Consul, GitHub, GitHubActions, ML 🏢 Description: Important things for you Flexible working hours in the hybrid model (4/1) - working hours start between 7:00 a.m. and 10:00 a.m. We also have 30 days of occasional remote work. The salary range for this position depending on the skill set is as follows (contract of employment, tax-deductible cost): PLN 11 200 - 15 250 Annual bonus based on your annual performance and company results. Our team is based in Warsaw. About the job Massive Scale : Design, build, and optimize systems that handle thousands of requests per minute. This is high-availability, high-performance engineering in practice. Modern Tech Stack : Work with a world-class, cloud-native environment. Our core technologies include Kotlin, Spring, Kafka, and Kubernetes. We're not shy when it comes to ML too :) True Ownership & Autonomy : We live by a "you build it, you run it" philosophy. You'll join an agile, autonomous team with full ownership of your microservices, from design to deployment. Complex Challenges : From distributed systems and data streaming to algorithmic optimization, you'll tackle the complex backend problems that power a massive, real-time marketplace. End-to-End ML Systems: Bridge the gap between big data and real-time product impact. You’ll build the infrastructure for serving ML models , using BigQuery and Apache Spark for offline data processing. You’ll integrate these components with our microservices architecture to create the sophisticated advertising system that powers a personalized user experience. Join the Advertising team! You will have a chance to build Allegro Ads - one of the most visible products on the platform. Your team works closely with the Machine Learning team, creating the best experience for customers. High performance, engineering best practices and great atmosphere in the team guaranteed! We are looking for people who: Code in Kotlin or Java and are eager to master Kotlin by taking part greenfield project Want to be proud of the code they create ; they value high-quality code reviews and engage in substantive discussions on software engineering best practices; Are excited about building new products and want to experience the journey of launching a fresh project within the Allegro ecosystem; Are open to developing soft skills and embracing a growth mindset through active participation in code reviews, pair programming, and team retrospectives.; Are open to incorporating AI coding assistants into their daily work to maximize efficiency and focus on complex problem-solving Can look for effective solutions to the requirements set by users; Want to constantly develop and update their knowledge; Know English at at least B2 level. What's in it for you: Well-located offices (with e.g. fully equipped kitchens, bicycle parking, terraces full of greenery) and excellent work tools (e.g., raised desks, ergonomic chairs, interactive conference rooms). A 16" or 14" MacBook Pro or corresponding Dell with Windows (if you don't like Macs) and all the necessary accessories. A wide selection of fringe benefits in a cafeteria plan - you choose what you like (e.g., medical, sports or lunch packages, insurance, purchase vouchers). English classes that we pay for related to the specific nature of your job. A training budget, inter-team tourism ( see more here ), hackathons, and an internal learning platform where you will find multiple trainings. An additional day off for volunteering, which you can use alone, with a team, or with a larger group of people connected by a common goal. Social events for Allegro people - Spin Kilometers, Family Day, Fat Thursday, Advent of Code, and many other occasions we enjoy. And that's just the beginning! You can read more about the benefits here . #goodtobehere means that: You will join a team you can count on - we work with top-class specialists who have knowledge- and experience-sharing in their DNA. You will love our level of autonomy in team organization, the space for continuous development, and the opportunity to try new things. You get to choose which technology solves the problem and you are responsible for what you create. You will value our Developer Experience and the full platform of tools and technologies that make creating software easier. We rely on an internal ecosystem based on self-service and widely used tools such as Kubernetes, Docker, Consul, GitHub, and GitHub Actions. Thanks to this, you can contribute to Allegro from your very first days on the job. You will be equipped with modern AI tools to automate repetitive tasks, allowing you to focus on developing new services and refining existing ones (also leveraging AI support). You will create solutions that will be used (and loved!) by your friends, family and millions of our customers. You will meet the Allegro Scale , which starts with over 1000 microservices, an open-source data bus (Hermes) with 300K+ rps, a Service Mesh with 1M+ rps, tens of petabytes of data, and production-used machine learning. You will become part of Allegro Tech - We speak at industry conferences, cooperate with tech communities, run our own blog (it's been over 10 years!), record podcasts, lead guilds, and we organize our own internal conference - the Allegro Tech Meeting. We create solutions we love (and can) to talk about! Send us your CV and… see you at Allegro!

🏢 Summary: Senior/Staff Backend Engineer role focused on building and evolving a large-scale, event-driven platform using Java, Kafka Streams, and AWS. The position involves hands-on work with high-volume data flows, real-time stream processing, distributed systems, and production reliability. You will take strong technical ownership in a small team, shaping architecture, standards, and production readiness. 🗂️ Requirements: 7+ years of backend engineering experience, Strong hands-on experience with Java, Strong hands-on experience with Spring Boot, Deep production experience with Kafka Streams (topologies, joins, aggregations, windowing, state stores), Experience with event-driven or distributed systems, Hands-on experience with AWS services, Experience with Kubernetes and containerized deployments, Experience with PostgreSQL, MongoDB, and Redis, Strong knowledge of monitoring, debugging, and performance optimization, Ability to work independently in evolving technical environments, Professional English communication skills 📃 Skills: Java, Spring, Kafka, KafkaStreams, AWS, EKS, S3, SQS, SNS, Kinesis, Lambda, Kubernetes, PostgreSQL, MongoDB, Redis, Terraform, Helm, Prometheus, Grafana, Micrometer, Kotlin 🏢 Description: Senior / Staff Backend Engineer (Java, Kafka Streams, AWS) Location: Kraków, hybrid Contract: B2B or UoP B2B budget: up to 210 PLN/h + VAT Work model: around 3 days per week from the office We are looking for a Senior or Staff Backend Engineer to join a small, high-impact engineering team building a large-scale, event-driven platform. This is a hands-on role for someone who enjoys working close to real production systems: high-volume data flows, asynchronous processing, external integrations, reliability, observability and technical ownership. You will join a team where the codebase and domain are evolving, so this is a good opportunity for an engineer who does not need every problem to be fully defined before getting started. You will be expected to investigate, create structure, improve standards and make pragmatic technical decisions. What you will do Build and evolve backend services using Java and Spring Boot Design and maintain real-time event-processing flows using Kafka Streams Work with stream-processing concepts such as topologies, transformations, joins, aggregations, stateful processing and data routing Integrate external systems and infrastructure into a scalable internal platform Improve reliability, observability and production readiness of services handling high-volume data Investigate production issues, performance bottlenecks and data-flow problems Work with AWS, Kubernetes, PostgreSQL, MongoDB, Redis, Terraform and Helm Contribute to code reviews, architecture decisions, documentation and engineering standards Collaborate with product, platform and engineering stakeholders across an international environment What we are looking for 7+ years of backend engineering experience Strong, current hands-on experience with Java and Spring Boot Deep practical experience with Kafka Streams in production This should go beyond Kafka producers/consumers and include work with stream-processing logic, joins, aggregations, windowing, state stores or topology design Background in event-driven, distributed or real-time systems Hands-on AWS experience, ideally with services such as EKS, S3, SQS, SNS, Kinesis or Lambda Experience with Kubernetes , containers and production deployment environments Good understanding of databases such as PostgreSQL, MongoDB and Redis Strong production mindset: monitoring, debugging, reliability, performance and incident investigation Ability to work independently in an evolving and not always fully documented technical environment Clear English communication skills and confidence explaining technical topics to both engineers and non-technical stakeholders Nice to have Kotlin experience Experience with high-throughput data processing or streaming platforms Terraform, Helm, Prometheus, Grafana, Micrometer or similar observability tooling Experience in a small product team, scale-up or ownership-heavy engineering environment Familiarity with AI-assisted development tools What you can expect A technically challenging role focused on real production systems rather than isolated feature delivery Strong ownership Small team setup with room to influence architecture, standards and ways of working International engineering environment Clear recruitment process focused on practical engineering discussions Recruitment process Introductory conversation with the Hiring Manager Technical interview focused on Kafka/use cases and Java/code quality Final discussion with senior technical leadership The full company and product context will be shared during the first recruiter call.

🏢 Summary: Remote B2B offer for an experienced Java Developer to design and build scalable REST APIs and broker integrations using Spring-based technologies within a microservices architecture. The role focuses on high-quality API development, SQL database management, and system design in a Scrum team. The position involves international collaboration and participation in architecture and integration initiatives. 🗂️ Requirements: Minimum 5 years of experience with Java (8/17/21), Strong knowledge of Spring Framework, Strong knowledge of Hibernate, Experience with REST API design and development, Experience with microservices architecture, Strong SQL and relational database expertise, Knowledge of architectural and design patterns, Experience with Git, Experience with TeamCity, Polish proficiency, English proficiency 📃 Skills: Java, Spring, Hibernate, SQL, REST, Microservices, Git, TeamCity, Maven, Scrum, RelationalDatabases, DesignPatterns 🏢 Description: Work model: remote, visit in the office once a quater in Warszawa Rate: up to 150 PLN/h (B2B contract) We are looking for a motivated Java Developer to join our team focused on building and evolving API integrations with external brokers. The ideal candidate will possess a strong background in Java, Spring-based technologies, and a deep understanding of systems integration and microservices architecture. You will contribute significantly to developing high-quality, maintainable APIs that enable seamless integration with various partners across multiple international markets. We work in a cross-functional team utilizing Scrum methodology. Main Responsibilities Design and build high-quality APIs using Java (8/17/21) and Spring-based technologies, ensuring scalability and maintainability. Develop and enhance broker integrations, contributing to business growth and market expansion. Contribute to modern service-oriented architecture design applying microservices knowledge. Manage SQL databases and ensure data consistency and reliability in applications. Utilize tools like Git, Maven, and TeamCity for continuous integration and code delivery. Collaborate on frontend API usability to ensure practical and well-structured solutions. Communicate effectively in Polish and English to facilitate international collaboration. Key Requirements At least 5 years of experience with Java (8/17/21 ) Deep knowledge of the Spring Framework and Hibernate. Strong SQL and relational database expertise. Strong problem-solving skills and proactive attitude. Experience in clean REST API design and development. Familiarity with microservices architecture. Knowledge of architectural and design patterns. Experience with Git and TeamCity. Polish and English proficiency. Nice to Have Experience with React for effective collaboration with frontend developers. Experience with large-scale applications using Maven. Knowledge of Apache Kafka. Experience with Domain-Driven Design (DDD) or Hexagonal architecture. Experience in decoupling monolithic applications. Background in the fintech industry. Recruitment process: 1. Live coding session 2. System design session 3. HR interview

🏢 Summary: Remote Software Engineer (Java) role focused on designing and delivering scalable back-end solutions for a strategic financial domain initiative. The position involves full ownership of the software development lifecycle, from requirements to deployment, within an Agile environment. The engineer will work with modern cloud-native technologies and collaborate with cross-functional international teams. 🗂️ Requirements: Proficiency in Java, Strong experience with Spring Boot, Experience with Kafka, Experience with Docker and Kubernetes, Knowledge of Hibernate, Experience with Microservices architecture, Experience with CI/CD tools, Experience with cloud platforms (AWS, Azure or GCP), Understanding of unit testing, Experience building REST APIs, Knowledge of security best practices, Fluent English, Location in Poland 📃 Skills: Java, Spring, SpringBoot, Kafka, Docker, Kubernetes, Hibernate, Microservices, Jenkins, GitHubActions, AWS, Azure, GCP, REST, CI/CD, Agile, Scrum 🏢 Description: Software Engineer (Java) Salary: 100-130 pln/h Work Model : Remote with visits to Warszawa, Gdańsk or Wrocław office once per month Join our expanding engineering team supporting a strategic initiative in the financial domain. As a global tech partner with over 30 years of experience, we help leading organizations modernize their systems and deliver top-tier digital solutions. We’re looking for a Software Engineer (Java) who thrives in ownership-driven environments and enjoys solving complex technical challenges. What You’ll Do •             Design and build scalable back-end solutions using Java and Spring Boot •             Own the full software development lifecycle: from requirements gathering to deployment and monitoring •             Collaborate with cross-functional teams and stakeholders •             Drive engineering excellence and mentor others What You Bring •             Proficiency in Java, with strong experience in Spring Boot, Kafka, Docker, and Kubernetes •             Solid knowledge of Hibernate and Microservices architecture •             Experience with CI/CD tools (Jenkins, GitHub Actions) and cloud platforms (AWS, Azure, or GCP) •             Strong understanding of unit testing, REST APIs, and security best practices •             Excellent communication skills, team collaboration, and ownership mindset •             Fluent in English •             Must be located in Poland Agile Experience •             Hands-on experience with Agile/Scrum methodologies •             Comfortable working in fast-paced environments with evolving priorities Nice to Have •             Background in financial services What we Offer •             Work in international teams (Poland, UK, US). •             Remote-first work model

🏢 Summary: Remote position for an experienced full‑stack developer responsible for building new APIs, maintaining and upgrading backend and frontend applications, and improving product quality. The role involves bug fixing and continuous enhancement of existing systems using modern Java and JavaScript technologies. Salary depends on experience (3+ years). 🗂️ Requirements: Minimum 3 years of experience with Java, Minimum 3 years of experience with AWS, Minimum 3 years of experience with MongoDB, Minimum 3 years of experience with PostgreSQL, Minimum 3 years of experience with React.js, Minimum 3 years of experience with Spring Boot 📃 Skills: Java, AWS, MongoDB, PostgreSQL, React, SpringBoot, APIs 🏢 Description: Location: 100% remote Salary: 105–175 PLN net/h ( depending on experience, we are looking for candidates with 3 to +8 years of experience ) Tasks Development of new APIs to support clients Fixing bugs Upgrading and maintaining backend and frontend applications Looking for opportunities to improve the product Requirements Java – minimum 3 years of experience AWS – minimum 3 years of experience MongoDB – minimum 3 years of experience PostgreSQL – minimum 3 years of experience React.js – minimum 3 years of experience Spring Boot – minimum 3 years of experience Offer Multisport card Private healthcare Access to an e‑learning platform Group life insurance