Freelance Kotlin Developer (Fulltime)

🏢 Summary: The offer is for a Backend Developer role focused on building and maintaining high-performance, low-latency systems for advertising and e-commerce platforms. The position involves developing scalable microservices and APIs using Kotlin and Spring Boot, working with real-time event processing, and contributing to system architecture and scalability. The role also includes production support and collaboration within cross-functional engineering teams. 🗂️ Requirements: 3+ years of professional experience in Java backend development, Very good knowledge of Kotlin, Very good knowledge of Spring Boot, Hands-on experience with microservices architecture, Practical experience with NoSQL databases, Experience with MongoDB, Experience building and maintaining backend systems and APIs, Understanding of system design and scalable architecture principles, Experience with high-performance and high-scale systems, English level B2, Polish level C1, Experience with AI-powered coding assistants, Work permit for EU and ability to work from EU region, Availability for occasional visits to Warsaw office 📃 Skills: Java, Kotlin, Spring, SpringBoot, Microservices, MongoDB, NoSQL, REST, API, AI, Claude, Copilot, Cursor 🏢 Description: 🟣 You will be: developing and maintaining backend systems for advertising and e-commerce platforms, building low-latency, high-performance services processing large volumes of data, developing scalable microservices and APIs using Kotlin and Spring Boot, working on real-time event processing and advertising targeting mechanisms, contributing to architecture design and system scalability improvements, collaborating with stakeholders and supporting engineering best practices, including code reviews and code quality standards, participating in technical readiness/on-call support for production incidents a few days per month. 🟣 Your profile: 3+ years of professional experience in Java backend development, very good knowledge of Kotlin and Spring Boot, openness to occasional visits to the Warsaw office (1–2 days per quarter), hands-on experience with microservices architecture, practical experience working with NoSQL databases, especially MongoDB, experience building and maintaining backend systems and APIs, understanding of system design and scalable architecture principles, experience working with high-performance and high-scale systems, strong analytical thinking and problem-solving skills, ability to collaborate effectively with stakeholders and engineering teams, good communication skills in English (B2) and Polish (C1), practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery. immediate availability or a short notice period is preferred. Work from the European Union region and a work permit are required. 🟣 Nice to have: experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work, interest in and familiarity with emerging AI-driven practices (e.g. agent-based workflows, automation patterns, AI-augmented development), with a willingness to explore and experiment beyond standard approaches. 🟣 Recruitment Process: CV review – HR call – Technical Interview – Client Interview – Decision 🎁 Benefits 🎁 ✍ Development: development budgets of up to 6,800 PLN, we fund certifications e.g.: AWS, Azure, access to Udemy, O'Reilly (formerly Safari Books Online) and more, events and technology conferences, technology Guilds, internal training, Xebia Upskill. 🩺 We take care of your health: private medical healthcare, multiSport card - we subsidise a MultiSport card, mental Health Support. 🤸‍♂️ We are flexible: B2B or employment contract, contract for an indefinite period.

🏢 Summary: The role involves developing and maintaining high-performance backend systems for advertising and e-commerce platforms, focusing on scalable microservices and real-time data processing using Kotlin and Spring Boot. You will design low-latency services, contribute to system architecture, and support production environments in a high-scale setting. The position also emphasizes AI-assisted development practices and collaboration within engineering teams. 🗂️ Requirements: 3+ years of backend development experience, Very good knowledge of Kotlin, Very good knowledge of Spring Boot, Hands-on experience with microservices architecture, Experience with NoSQL databases, Experience with MongoDB, Experience building and maintaining backend systems and APIs, Understanding of system design and scalable architecture, Experience with high-performance and high-scale systems, English B2 level, Polish C1 level, Work permit in the European Union, Openness to occasional visits to Warsaw office, Experience using AI-powered coding assistants 📃 Skills: Kotlin, SpringBoot, MongoDB, NoSQL, Microservices, REST, APIs, GenAI, Claude, GitHubCopilot, Cursor, AWS, Azure 🏢 Description: 🟣 You will be: developing and maintaining backend systems for advertising and e-commerce platforms, building low-latency, high-performance services processing large volumes of data, developing scalable microservices and APIs using Kotlin and Spring Boot, working on real-time event processing and advertising targeting mechanisms, contributing to architecture design and system scalability improvements, collaborating with stakeholders and supporting engineering best practices, including code reviews and code quality standards, participating in technical readiness/on-call support for production incidents a few days per month. 🟣 Your profile: 3+ years of professional experience in backend development, very good knowledge of Kotlin and Spring Boot, openness to occasional visits to the Warsaw office (1–2 days per quarter), hands-on experience with microservices architecture, practical experience working with NoSQL databases, especially MongoDB, experience building and maintaining backend systems and APIs, understanding of system design and scalable architecture principles, experience working with high-performance and high-scale systems, strong analytical thinking and problem-solving skills, ability to collaborate effectively with stakeholders and engineering teams, good communication skills in English (B2) and Polish (C1), practical experience using AI-powered assistants (e.g. Claude Code, GitHub Copilot, Cursor) to improve productivity, quality, or decision-making in software delivery. Work from the European Union region and a work permit are required. 🟣 Nice to have: experience applying GenAI in a more structured way within the SDLC, including defined workflows, prompt patterns, or tool integrations embedded into daily work, interest in and familiarity with emerging AI-driven practices (e.g. agent-based workflows, automation patterns, AI-augmented development), with a willingness to explore and experiment beyond standard approaches. 🟣 Recruitment Process: CV review – HR call – Technical Interview – Client Interview – Decision 🎁 Benefits 🎁 ✍ Development: development budgets of up to 6,800 PLN, we fund certifications e.g.: AWS, Azure, access to Udemy, O'Reilly (formerly Safari Books Online) and more, events and technology conferences, technology Guilds, internal training, Xebia Upskill. 🩺 We take care of your health: private medical healthcare, multiSport card - we subsidise a MultiSport card, mental Health Support. 🤸‍♂️ We are flexible: B2B or employment contract, contract for an indefinite period.

🏢 Summary: Senior backend engineering role focused on designing and scaling assortment management systems in a large retail ecosystem using Kotlin, Spring Boot, Kafka, AWS, and Kubernetes. The position involves building distributed, event-driven services, leading backend architecture evolution, and collaborating with cross-functional teams to deliver scalable enterprise solutions. The role also includes mentoring engineers, driving engineering best practices, and improving system reliability and observability. 🗂️ Requirements: Degree in Computer Science or comparable technical field, 6+ years of backend development experience, Experience with Kotlin, Experience with Spring Boot, Expertise in 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, Experience with CI/CD, Experience with containerization, Knowledge of observability tooling, Knowledge of OAuth2, Knowledge of IAM, English proficiency, Polish proficiency, Readiness to work in hybrid model 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. 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: 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 engineering role focused on designing and operating large-scale batch and streaming data pipeline platforms with strong reliability and performance requirements. The position involves building distributed systems, pipeline orchestration services, and cloud-native platform capabilities using Java and modern data technologies. The role also includes technical leadership, CI/CD improvements, and collaboration across international engineering teams. 🗂️ Requirements: Strong backend engineering experience with Java, Experience building production-grade distributed systems, Expertise in software architecture and system design, Experience with high-throughput and low-latency systems, Knowledge of REST APIs and microservices, Hands-on experience with AWS and cloud-native design, Experience with Docker and Kubernetes, Experience with Flink, Spark, or Kafka, Familiarity with CI/CD pipelines and DevOps practices, Experience with Jenkins, GitLab, Git, and JIRA, Strong communication skills 📃 Skills: Java, Flink, Spark, Kafka, AWS, EMR, S3, REST, Microservices, Docker, Kubernetes, Jenkins, GitLab, Git, JIRA, HTTP 🏢 Description: The Pipeline Management team builds and operates a core platform that powers large-scale batch and streaming data pipelines across HERE’s Data Platform. Our platform enables internal teams and customers to design, deploy, and operate data pipelines at scale, supporting mission-critical workloads with strong reliability and performance requirements. Lead the design and development of pipeline management services and APIs Own and evolve key platform components, including pipeline orchestration, scheduling, and workflow state management Drive architecture for high-throughput, low-latency distributed systems Partner with Product and engineering teams to deliver scalable data platform capabilities Mentor engineers and provide technical leadership across a distributed team Improve system reliability, observability, and SLA adherence for production services Contribute to CI/CD, automation, and engineering best practices across the platform Technology Stack: You will work with a modern data platform ecosystem including: Data Processing: Apache Flink, Apache Spark Backend & Services: Java (primary), REST APIs, microservices Streaming & Messaging: Apache Kafka Cloud & Infrastructure: AWS (EMR, S3) Platform Services: Pipeline Service, Scheduler, State Service, Coordinator CI/CD & Tooling: Jenkins, GitLab pipelines, Git, JIRA Who are you? Strong backend engineering experience with Java (preferred), building production-grade distributed systems Expertise in software architecture and system design Experience building and operating high-throughput, low-latency, highly reliable distributed systems Solid understanding of REST APIs, HTTP, and microservices architectures Hands-on experience with cloud platforms (AWS preferred) and cloud-native design Experience with containerization and orchestration (Docker, Kubernetes) Experience with data processing and streaming systems (e.g., Flink, Spark, Kafka) Strong familiarity with CI/CD pipelines and engineering tools (e.g., Jenkins, GitLab, Git, JIRA) Experience applying DevOps practices to improve system reliability and delivery velocity Strong communication skills with the ability to clearly explain complex concepts Nice to Have Experience with pipeline orchestration platforms or workflow engines Exposure to large-scale data platforms or multi-tenant systems Experience with cloud platform migrations or modernization initiatives What we offer: Work on on globally deployed automotive navigation and mapping products Collaboration with an experienced, international engineering organization Truly international team of fantastic & talented people from 60+ countries worldwide, working from strong tech hubs located in Europe, the US, and Asia, along with multiple smaller locations Flexible working hours & a flexible approach to office vs. remote work Medical coverage for you and your family Yearly variable bonus This role is eligible for the Creative Tax Incentive scheme in Poland (KUP) Option to work on a B2B contract (please note: benefits, bonus and KUP do not apply in this case)

🏢 Summary: Backend and Cloud Engineer role focused on designing and scaling IoT-driven, cloud-native platforms in AWS. The position involves building distributed backend services, event-driven architectures, and telemetry processing systems while owning infrastructure and CI/CD pipelines. The engineer contributes to architecture decisions and ensures secure, scalable, and production-ready solutions. 🗂️ Requirements: University degree in Computer Science or related field, 5+ years of backend engineering experience, Strong expertise in TypeScript and Node.js, Hands-on experience with NestJS and scalable REST APIs, Deep experience with AWS services including IoT Core, Lambda, Kinesis, SQS, Timestream, IAM, CloudWatch, Experience with infrastructure as code and Kubernetes, Experience with containerization and CI/CD pipelines, Strong knowledge of distributed systems and event-driven architectures, Experience with IoT communication patterns such as MQTT, Fluent English and Polish, Availability for hybrid work (1–2 office visits per week) 📃 Skills: TypeScript, Node.js, NestJS, Fastify, REST, OpenAPI, AWS, IoT, IoTCore, Lambda, Kinesis, SQS, Timestream, IAM, CloudWatch, MQTT, PostgreSQL, Aurora, Terraform, OpenTofu, Kubernetes, Helm, GitLab, CI/CD 🏢 Description: Responsibilities We are looking for a strong backend and cloud engineer with deep experience in IoT and distributed systems who wants to shape and scale modern cloud - native platforms . You will design and evolve IoT and cloud architectures at OBI Smart Technologies Poland , working across device communication , telemetry processing and automation workflows . You act as a technical driver within the team, contributing to architecture decisions and ensuring scalable, secure and production-ready solutions across AWS environments . Your key responsibilities include: Design and develop scalable backend services using TypeScript, Node.js, NestJS and Fastify within distributed systems. Lead the design and evolution of REST APIs using OpenAPI standards and robust validation and versioning strategies. Design and operate AWS - native IoT and event-driven architectures using IoT Core, MQTT, Lambda, Kinesis and related services. Build scalable data processing and automation workflows for telemetry and energy-related data using Timestream , SQS and streaming services . Design and optimize persistence layers using PostgreSQL or Aurora and ensure data consistency and performance. Own infrastructure and deployment design using Terraform or OpenTofu , Kubernetes , Helm and GitLab CI/CD pipelines . Drive engineering best practices , observability , reliability and security standards while supporting GDPR-related backend processes and mentoring team members. 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. 5+ years of professional experience in backend engineering with strong expertise in TypeScript and Node . js . Strong hands-on experience with NestJS and designing scalable REST APIs in production environments. Deep experience with AWS cloud services including IoT Core , Lambda , Kinesis , SQS , Timestream , IAM and CloudWatch . Strong experience with infrastructure as code , Kubernetes , containerization and CI/CD pipelines . Solid understanding of distributed systems, event-driven architectures and IoT communication patterns such as MQTT . Ability to translate complex business requirements into scalable technical solutions. Fluent communication skills in English and Polish and availability to work in a hybrid mode with 1–2 office visits per week. 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: Mid-Level/Senior Kotlin (Java) Developer role focused on designing and building microservices and APIs within a compliance management platform. The position involves developing backend and web applications in a microservice architecture, contributing to CI/CD processes, and delivering high-quality solutions in an agile environment. Hybrid work model based in Kraków with up to 3 days of remote work per week. 🗂️ Requirements: 4+ years of software development experience, Experience in backend and API development, Proficiency in Kotlin or Java, Experience with API development, Experience with SQL and databases, Experience with HTML and JavaScript, Understanding of microservice architecture, Experience working in Agile environments, Knowledge of Jira and Confluence, Fluent English (B2+ level), Legal right to work in the European Union 📃 Skills: Kotlin, Java, SQL, HTML, JavaScript, Microservices, APIs, CI/CD, Jira, Confluence, AWS, Azure, GCP, Jenkins, Linux, AIX, WebSphere 🏢 Description: Unleash innovation — design cutting-edge microservices and APIs that drive digital transformation! Kraków-based opportunity with hybrid work model (up to 3 days remote per week). As a Mid-Level/Senior Kotlin (Java) Developer , you will be working for our client, a forward-thinking organization building a platform for control owners and development teams to manage and monitor software development compliance. You will contribute to Kotlin and Java-based web applications and APIs within a microservice architecture, supporting innovative solutions across multiple applications and PoCs. This role offers a unique chance to shape the future of development standards while advancing your career in a dynamic environment. Your main responsibilities: Collaborate with cross-functional teams to develop and operate products that meet strategic goals. Design, develop, and implement both front-end and back-end features that support flexible UI frameworks. Build efficient APIs and microservices to address impactful business needs. Work within an agile CI/CD environment to deliver continuous improvements at high velocity. Engage in peer reviews, testing, and automated test scripting to ensure high-quality code. Proactively troubleshoot issues and respond to customer feature requests with innovative solutions. You're ideal for this role if you have: 4+ years of experience in software development, with a focus on backend and API development. Solid expertise in Kotlin or Java (with a willingness to learn Kotlin). Hands-on experience with API development, SQL/databases, and HTML/JavaScript. Strong problem-solving and troubleshooting skills. Experience working in Agile environments with tools like Jira and Confluence. Good understanding of microservice architecture. Excellent interpersonal and communication skills in English (B2+ level). It is a strong plus if you have: Good working knowledge of cloud platforms such as AWS, Azure, or GCP. Experience building CI/CD pipelines using Jenkins. Background in Systems Administration across Linux, AIX, or WebSphere platforms. Language Required for the role: Fluent English (B2+ level). Eligibility to work in Europe: Only candidates with an existing legal right to work in the European Union will be considered for this role. #MAKEYourCareerBETTER Interested? Apply now and include your CV (preferably in English) along with a statement confirming your consent to the processing and storage of your personal data.

🏢 Summary: The offer is for a senior backend and cloud engineer to design and scale IoT-driven, cloud-native platforms on AWS. The role focuses on building distributed systems, event-driven architectures, and scalable REST APIs using TypeScript and Node.js. It includes ownership of infrastructure, data processing workflows, and cloud-native deployments in production environments. 🗂️ Requirements: Completed degree in Computer Science or related field, 5+ years of backend engineering experience, Strong expertise in TypeScript, Strong expertise in Node.js, Hands-on experience with NestJS, Experience designing scalable REST APIs in production, Deep experience with AWS services, Experience with infrastructure as code, Experience with Kubernetes and containerization, Experience with CI/CD pipelines, Strong understanding of distributed systems, Knowledge of event-driven architectures, Experience with MQTT and IoT communication, Fluent English, Fluent Polish, Availability for hybrid work (1–2 days onsite per week) 📃 Skills: TypeScript, Node.js, NestJS, Fastify, REST, OpenAPI, AWS, IoT, IoTCore, Lambda, Kinesis, SQS, Timestream, IAM, CloudWatch, MQTT, PostgreSQL, Aurora, Terraform, OpenTofu, Kubernetes, Helm, GitLab, CI/CD 🏢 Description: Responsibilities We are looking for a strong backend and cloud engineer with deep experience in IoT and distributed systems who wants to shape and scale modern cloud - native platforms . You will design and evolve IoT and cloud architectures at OBI Smart Technologies Poland , working across device communication , telemetry processing and automation workflows . You act as a technical driver within the team, contributing to architecture decisions and ensuring scalable, secure and production-ready solutions across AWS environments . Your key responsibilities include: Design and develop scalable backend services using TypeScript, Node.js, NestJS and Fastify within distributed systems. Lead the design and evolution of REST APIs using OpenAPI standards and robust validation and versioning strategies. Design and operate AWS - native IoT and event-driven architectures using IoT Core, MQTT, Lambda, Kinesis and related services. Build scalable data processing and automation workflows for telemetry and energy-related data using Timestream , SQS and streaming services . Design and optimize persistence layers using PostgreSQL or Aurora and ensure data consistency and performance. Own infrastructure and deployment design using Terraform or OpenTofu , Kubernetes , Helm and GitLab CI/CD pipelines . Drive engineering best practices , observability , reliability and security standards while supporting GDPR-related backend processes and mentoring team members. Qualifications Completed university degree in Computer Science or a comparable technical field. 5+ years of professional experience in backend engineering with strong expertise in TypeScript and Node . js . Strong hands-on experience with NestJS and designing scalable REST APIs in production environments. Deep experience with AWS cloud services including IoT Core , Lambda , Kinesis , SQS , Timestream , IAM and CloudWatch . Strong experience with infrastructure as code , Kubernetes , containerization and CI/CD pipelines . Solid understanding of distributed systems, event-driven architectures and IoT communication patterns such as MQTT . Ability to translate complex business requirements into scalable technical solutions. Fluent communication skills in English and Polish and availability to work in a hybrid mode with 1–2 office visits per week. 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: Backend Developer role focused on designing, building, and maintaining scalable Java and Kotlin-based applications and microservices within an international team. The position involves developing high-quality backend systems, collaborating with cross-functional teams, and optimizing distributed systems performance. The role emphasizes clean code, modern frameworks, and agile delivery practices. 🗂️ Requirements: 5+ years of backend development experience with Java 8+ and Kotlin, Strong knowledge of Spring Framework and Spring Boot, Experience building RESTful APIs and microservices, Experience with SQL and NoSQL databases, Understanding of Agile/Scrum methodologies 📃 Skills: Java, Kotlin, Spring, SpringBoot, REST, Microservices, SQL, NoSQL, PostgreSQL, MongoDB, Agile, Scrum 🏢 Description: We are looking for skilled Java & Kotlin Developers to join our growing technology team in Poland. As part of an international development group, you’ll design, build, and maintain scalable backend systems using Java and modern frameworks. You’ll collaborate closely with cross-functional teams to deliver high-quality, reliable, and efficient software solutions. Key Responsibilities Design, develop, and maintain Java-based applications and microservices. Write clean, efficient, and testable code following best practices and coding standards. Collaborate with front-end developers , DevOps engineers , and QA teams to ensure seamless integration and delivery. Participate in code reviews , architecture discussions, and agile ceremonies. Contribute to technical documentation and continuous improvement of development processes. Troubleshoot and optimize performance across distributed systems. Requirements 5+ years of experience in backend development using Java 8+ Kotlin . Strong understanding of Spring Framework / Spring Boot . Experience with RESTful APIs , microservices , and SQL / NoSQL databases (e.g., PostgreSQL, MongoDB). Knowledge of Agile / Scrum methodologies. Good command of English (B2 or higher) – Polish language skills are a plus. Nice to Have Experience with cloud platforms (AWS, Azure, or GCP). Familiarity with message brokers (Kafka, RabbitMQ). Knowledge of unit testing and test automation frameworks (JUnit, Mockito). Interest in DevOps or system design concepts. How to Apply If you’re passionate about building high-quality Java applications and want to be part of a dynamic engineering team, send your CV

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