Fullstack Developer (React / TypeScript / .NET) (B2B)

🏢 Summary: Full Stack Developer role with a strong frontend focus, responsible for building scalable modern web applications using React and TypeScript while contributing to backend services in .NET. The position involves delivering end-to-end features, integrating REST APIs, and ensuring high performance across frontend and backend layers in an agile environment. 🗂️ Requirements: Completed degree in Computer Science or related technical field, Strong commercial experience with React, Strong commercial experience with TypeScript, Solid understanding of modern frontend architecture and performance optimization, Experience building scalable and maintainable web applications, Good understanding of REST APIs and backend integration, Experience with C#, Experience with .NET development, Experience working in agile development environments, Understanding of software development lifecycle 📃 Skills: React, TypeScript, C#, .NET, REST, APIs, Agile, SDLC 🏢 Description: Responsibilities We are looking for a Full Stack Developer with a strong frontend focus who wants to work on modern web applications in an international environment. You will design and develop scalable business applications, primarily using React and TypeScript , while also contributing to backend services and integrations. You collaborate closely with product owners, architects, and engineering teams to deliver end-to-end features across the full stack. Your key responsibilities include: Design, develop, and maintain modern web applications using React and TypeScript . Implement responsive, user-friendly and high-performance frontend solutions. Collaborate with backend engineers and architects to deliver end-to-end features . Develop and maintain backend services and APIs using .NET technologies. Troubleshoot , debug , and optimize application performance across frontend and backend layers. Work in an agile environment with cross-functional and international teams. Support application deployment , maintenance , and continuous improvement of systems. Contribute to technical discussions and help ensure code quality and maintainability . 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. Strong experience with React and TypeScript in production environments. Solid understanding of modern frontend architecture , performance , and best practices . Experience building scalable and maintainable web applications . Good understanding of REST APIs and backend integration concepts. Experience with C# and . NET development. Familiarity with agile methodologies and software development lifecycle . Fluent English and Polish communication skills and ability to work in international teams. Nice to have: Experience with MongoDB or other NoSQL databases. Knowledge of GraphQL and advanced API patterns. Exposure to Microsoft Azure and cloud - native architectures . Understanding of DevOps practices and CI/CD pipelines . Experience working in enterprise - scale or distributed systems environments . About Cluster Reply Cluster Reply is the Reply Group company specializing in consulting and system integration of Microsoft technologies. As a Microsoft partner, Cluster Reply is active in Germany, Austria and Switzerland and works within the Reply network with sister companies in Brazil, Great Britain, Italy as well as the USA. The company focuses on innovation and supports customers in their digital transformation. The solutions range from on-premises to cloud applications in the areas of modern workplace and security, business applications, applications and infrastructure as well as data and artificial intelligence.

🏢 Summary: Fullstack Developer role focused on building scalable web applications using ASP.NET, C#, and React, with strong emphasis on API design, event-driven architecture, and cloud-native environments. The position involves end-to-end development, CI/CD practices, containerized deployments, and collaboration in agile teams. Ideal for engineers experienced in backend services, modern frontend ecosystems, and orchestration tools. 🗂️ Requirements: Strong experience with ASP.NET, Strong experience with C#, Experience building scalable backend services and APIs, Strong experience with React, Understanding of modern frontend architecture, Experience with API design, Experience with GitLab CI/CD, Experience with RabbitMQ, Experience with Docker, Experience with Kubernetes 📃 Skills: ASP.NET, C#, React, TanStack, Tailwind, Playwright, RabbitMQ, Docker, Kubernetes, GitLab, Linux, Unity, APIs, CI/CD 🏢 Description: Role Overview We are looking for a skilled Fullstack Developer with strong backend expertise in ASP.NET and C#, combined with modern frontend development using React. The role involves building scalable web applications, designing robust APIs, and contributing to cloud-native and event-driven architectures. The ideal candidate is comfortable working across the full stack, collaborates well in agile teams, and has an interest in modern tooling, orchestration, and frontend ecosystems. Core Responsibilities • Design, develop, and maintain scalable fullstack applications • Build and maintain backend services using ASP.NET and C# • Develop responsive and modern frontend applications using React • Design and integrate APIs and asynchronous communication flows • Collaborate with developers, designers, QA, and DevOps teams • Contribute to architecture discussions and technical decisions • Ensure code quality through testing, reviews, and CI/CD practices • Participate in deployment, monitoring, and troubleshooting activities Must-Have Skills Backend • Strong experience with ASP.NET • Strong experience with C# • Experience building scalable backend services and APIs Frontend • Strong experience with React • Good understanding of modern frontend architecture and component-based development Should-Have Skills • Experience with GitLab Pipelines / CI-CD • Experience with API design and best practices Frontend Libraries & Tooling • Experience with: o TanStack o Tailwind CSS o Playwright o AI agent development (Kiro, Claude, Cursor) Messaging & Async Communication • Experience with: o RabbitMQ o Event-driven and asynchronous communication patterns • Understanding of async workflows across frontend and backend systems Infrastructure & Orchestration • Experience with: o Docker o Kubernetes • Familiarity with containerized deployments and orchestration Nice-to-Have Skills • Interest or experience in Unity / game development • Strong Linux competence Preferred Qualifications • Experience working in agile development environments • Strong problem-solving and debugging skills • Understanding of scalable and maintainable software architecture • Good communication and collaboration skills • Passion for learning modern technologies and frameworks Tech Stack Summary Area Backend: ASP.NET, C# Frontend: React Frontend Libraries: TanStack, Tailwind, Playwright Messaging: RabbitMQ Infrastructure: Docker, Kubernetes CI/CD: GitLab Pipelines Additional: Linux, API Design, Unity

🏢 Summary: Senior Full Stack Developer role focused on building enterprise-grade applications for capital markets and risk using React and C# .NET Core. The position involves developing scalable microservices, REST APIs, modern web UIs, and data-driven solutions in a cloud environment. Responsibilities include CI/CD implementation, event-driven architecture, cloud migration, and Power BI reporting. 🗂️ Requirements: Strong experience with React and TypeScript, Strong experience with C# and .NET Core, Experience building REST APIs, Experience developing microservices and distributed systems, Experience with CI/CD pipelines, Experience with Azure or AWS cloud platforms, Experience with Power BI and data modeling, Strong SQL and database knowledge, Experience with Docker and Kubernetes, Experience in capital markets domain especially credit risk or market risk, Strong understanding of software architecture and system design 📃 Skills: React, TypeScript, JavaScript, C#, DotNetCore, REST, Microservices, Azure, AWS, PowerBI, SQL, Docker, Kubernetes, Kafka, AzureDevOps, Jenkins, GitHubActions 🏢 Description: About the Role We are looking for a Senior Full Stack Developer with strong expertise in React on the frontend and C# .NET Core on the backend to build and enhance enterprise-grade applications in the capital markets and risk domain. The role involves developing scalable microservices, modern web applications, and data-driven solutions in a cloud environment. Key Responsibilities Design, develop, and maintain full stack applications using React and C# .NET Core Build and maintain REST APIs and microservices in distributed environments Develop modern, responsive UI components using React, TypeScript, and modern frontend patterns Work closely with business stakeholders in capital markets and risk domains (credit risk, market risk) Develop and maintain Power BI dashboards and data models for business reporting Implement and maintain CI/CD pipelines and automated deployment processes Contribute to event-driven architecture using tools such as Kafka or similar messaging technologies Participate in cloud migration and modernization initiatives (Azure or AWS) Ensure code quality through testing, code reviews, and best engineering practices Mentor junior developers and contribute to architectural decisions Requirements Strong experience with React, JavaScript/TypeScript Strong experience with C#, .NET Core, REST APIs Experience building microservices and distributed systems Experience with CI/CD tools (Azure DevOps, Jenkins, GitHub Actions) Experience with Azure or AWS Experience with Power BI and data modeling Strong SQL and database knowledge Experience with Docker / Kubernetes Experience working in capital markets , especially credit risk or market risk Strong understanding of software architecture and system design Excellent communication skills and experience working with business stakeholders

🏢 Summary: Fullstack Developer role focused on building and enhancing dynamic web applications using .NET on the backend and React on the frontend. The position involves developing robust, high-performance solutions, integrating APIs, and resolving complex technical issues within a collaborative team environment. Strong emphasis is placed on delivering seamless end-to-end functionality. 🗂️ Requirements: 5+ years of fullstack development experience, .NET backend expertise, Strong React knowledge, Experience with WCF and REST APIs, Database management experience, Proficiency in HTML, JavaScript, CSS, Understanding of message queues, Fluent English communication 📃 Skills: .NET, C#, React, REST, WCF, SQL, HTML, JavaScript, CSS, Databases, MessageQueues, English 🏢 Description: Summary: The ideal candidate is expected to function as a Fullstack Developer, contributing both front-end and back-end functionalities with a strong focus on .NET and React technologies. The primary goal is to enhance the team's capabilities in developing seamless, robust applications. Main Responsibilities: Engage in full-stack development to create dynamic web applications. Implement the front-end components using React. Develop back-end services using .NET. Communicate effectively with team members and stakeholders in English. Investigate and resolve complex technical problems proactively. Collaborate with team members to enhance application performance and usability. Key Requirements: 5+ years of experience in fullstack development. Expertise in .NET for backend development. Strong understanding of React for frontend development. Fluent communication skills in English. Knowledge of Web APIs (WCF and REST APIs). Familiarity with database management. Competence in HTML, JavaScript, and CSS. Understanding of message queues. Nice to Have: Experience with cloud services or platforms. Familiarity with CI/CD practices. Exposure to Agile methodologies.

🏢 Summary: Fullstack Developer role focused on building and enhancing dynamic web applications using .NET on the backend and React on the frontend. The position involves developing robust services, implementing responsive UI components, and resolving complex technical issues. The goal is to strengthen the team’s capability to deliver high-performance, scalable applications. 🗂️ Requirements: 5+ years of fullstack development experience, .NET expertise for backend development, Strong React knowledge for frontend development, Experience with Web APIs (WCF, REST), Database management experience, Proficiency in HTML, JavaScript, CSS, Understanding of message queues 📃 Skills: .NET, React, WCF, REST, WebAPI, HTML, JavaScript, CSS, SQL, Databases, MessageQueues 🏢 Description: Summary: The ideal candidate is expected to function as a Fullstack Developer, contributing both front-end and back-end functionalities with a strong focus on .NET and React technologies. The primary goal is to enhance the team's capabilities in developing seamless, robust applications. Main Responsibilities: Engage in full-stack development to create dynamic web applications. Implement the front-end components using React. Develop back-end services using .NET. Communicate effectively with team members and stakeholders in English. Investigate and resolve complex technical problems proactively. Collaborate with team members to enhance application performance and usability. Key Requirements: 5+ years of experience in fullstack development. Expertise in .NET for backend development. Strong understanding of React for frontend development. Fluent communication skills in English. Knowledge of Web APIs (WCF and REST APIs). Familiarity with database management. Competence in HTML, JavaScript, and CSS. Understanding of message queues. Nice to Have: Experience with cloud services or platforms. Familiarity with CI/CD practices. Exposure to Agile methodologies.

🏢 Summary: Hybrid Fullstack Developer role focused on building and maintaining scalable web applications using Java and React.js. The position involves designing backend services and RESTful APIs, developing modern frontend interfaces, and contributing to CI/CD and DevOps practices. Work includes testing, performance optimization, and collaboration on architecture and microservices. 🗂️ Requirements: Strong experience with Java and Spring Boot, Solid experience with React.js and state management, Experience designing and consuming RESTful APIs, Experience with microservices architecture, Proficiency in JavaScript, HTML5, CSS3, Experience with relational or NoSQL databases, Knowledge of unit and integration testing practices, Experience with CI/CD pipelines, Familiarity with Git and version control workflows, Ability to work with Agile/Scrum methodologies 📃 Skills: Java, Spring, SpringBoot, React, Redux, JavaScript, HTML5, CSS3, Webpack, Babel, ESLint, JUnit, Mockito, Jest, MySQL, PostgreSQL, NoSQL, Git, CI/CD, Docker, Kubernetes, AWS, Azure, GCP, Kafka, GraphQL, WebSocket 🏢 Description: We are looking for a highly skilled Fullstack Developer with expertise in Java and React.js to join our Kraków-based development team. You will design, develop, and maintain scalable, high-performance web applications, contributing to both backend services and rich frontend interfaces. This role follows a hybrid working model , with 2–3 days per week onsite in Kraków. Key Responsibilities Backend Development: Architect, implement, and maintain backend services using Java , Spring Boot , and related frameworks Frontend Development: Build responsive, modular, and maintainable React.js applications with a focus on component-driven design Design and implement RESTful APIs and microservices , ensuring high performance, security, and scalability Collaborate with cross-functional teams to define technical requirements , system architecture, and feature implementation Apply unit testing, integration testing, and end-to-end testing best practices (JUnit, Mockito, Jest, React Testing Library) Participate in code reviews , enforce coding standards, and promote best practices in clean code, SOLID principles, and design patterns Troubleshoot and optimize application performance and resolve production issues Manage CI/CD pipelines , automate deployments, and support DevOps practices Stay up-to-date with emerging technologies and frameworks to continuously improve application architecture Required Skills and Experience Strong experience with Java , Spring Boot , and related backend frameworks Solid experience with React.js , Redux , or state management libraries Proven experience in designing and consuming RESTful APIs and microservices architecture Proficient in JavaScript, HTML5, CSS3, and modern frontend tooling (Webpack, Babel, ESLint) Experience with relational databases (MySQL, PostgreSQL) and/or NoSQL databases Familiarity with Git , version control workflows, and Agile/Scrum methodologies Understanding of unit testing, integration testing, and test-driven development (TDD) Good problem-solving and communication skills in English Nice to Have Experience with TypeScript and advanced React patterns (Hooks, Context API, Suspense) Knowledge of Docker , Kubernetes , or cloud platforms (AWS, Azure, GCP) Experience with event-driven architectures , message queues , or Kafka Familiarity with GraphQL or WebSocket-based real-time applications

🏢 Summary: Full Stack Developer role focused on building scalable backend services in Java and modern, responsive front-end applications in React.js. The position involves designing RESTful APIs, collaborating with cross-functional teams, and delivering clean, maintainable, high-quality code in a hybrid work model. 🗂️ Requirements: Commercial experience with Java, Experience with Spring Boot framework, Strong knowledge of React.js, Proficiency in modern JavaScript, Experience designing and consuming RESTful APIs, Experience with relational or non-relational databases, Experience with version-controlled collaborative development, Availability to work onsite in hybrid model (Cracow) 📃 Skills: Java, SpringBoot, React, JavaScript, REST, SQL, NoSQL, AWS, Azure, GCP, Docker, Kubernetes, CICD 🏢 Description: 𝗪𝗲 𝗔𝗿𝗲 𝗛𝗶𝗿𝗶𝗻𝗴: 𝗝𝗮𝘃𝗮 𝗮𝗻𝗱 𝗥𝗲𝗮𝗰𝘁.𝗷𝘀 𝗙𝘂𝗹𝗹 𝗦𝘁𝗮𝗰𝗸 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿 We are currently seeking a skilled and motivated Full Stack Developer with strong expertise in Java and React.js to join our growing team. In this role, you will be responsible for designing and developing scalable backend services using Java, as well as building modern, responsive user interfaces using React.js. You will work closely with cross-functional teams to deliver high-quality, reliable solutions, while ensuring that your code is clean, maintainable, and efficient. 𝗞𝗲𝘆 𝗥𝗲𝘀𝗽𝗼𝗻𝘀𝗶𝗯𝗶𝗹𝗶𝘁𝗶𝗲𝘀: Developing robust backend applications using Java, ideally with Spring Boot Creating intuitive and high-performing front-end applications using React.js and modern JavaScript Designing and consuming RESTful application programming interfaces Collaborating with colleagues across engineering, product, and design teams Contributing to code reviews and continuous improvement practices 𝗪𝗲 𝗮𝗿𝗲 𝗹𝗼𝗼𝗸𝗶𝗻𝗴 𝗳𝗼𝗿 𝗰𝗮𝗻𝗱𝗶𝗱𝗮𝘁𝗲𝘀 𝘄𝗵𝗼 𝗵𝗮𝘃𝗲: Proven experience working with Java and related frameworks Strong knowledge of React.js and modern JavaScript standards Experience working with relational or non-relational databases A proactive approach to problem-solving and a strong attention to detail Excellent communication and teamwork skills It would be beneficial if you also have: Experience working with cloud platforms such as Amazon Web Services, Microsoft Azure, or Google Cloud Platform Exposure to continuous integration and continuous delivery pipelines Familiarity with containerisation technologies such as Docker and Kubernetes 📍 𝗟𝗼𝗰𝗮𝘁𝗶𝗼𝗻: Cracow, Poland (Hybrid – 3 days per week onsite) 💼 𝗘𝗺𝗽𝗹𝗼𝘆𝗺𝗲𝗻𝘁 𝗧𝘆𝗽𝗲: B2B If you are passionate about building impactful technology and are looking to take the next step in your career, we would be delighted to hear from you. Please apply or get in touch directly for more information.

🏢 Summary: Full-Stack Developer role focused on building and maintaining scalable server-side applications and responsive front-end interfaces using modern technologies. The position involves working with cloud and containerized environments, optimizing SQL Server databases, and contributing to architectural decisions. The role requires close collaboration with cross-functional teams to deliver high-quality software solutions. 🗂️ Requirements: 6+ years of full-stack application development experience, Proficiency in React, Proficiency in C#, Proficiency in ASP.NET, Proficiency in SQL, Experience with SQL Server and T-SQL, Ability to design and maintain server-side applications, Ability to develop responsive front-end interfaces 📃 Skills: C#, ASP.NET, .NET, React, AngularJS, Node.js, SQL, SQLServer, T-SQL, Cloud, Containers, Streaming 🏢 Description: Full-Stack Developer What you’ll do Design, develop, and maintain server-side applications using modern technologies such as C#/.NET and Node.js. Create and enhance responsive front-end interfaces with ReactJS and AngularJS. Optimize and manage SQL Server databases, writing efficient T-SQL procedures. Utilize cloud, containerization, and streaming technologies to build scalable and reliable systems. Contribute to architectural discussions and technical design decisions. Work closely with cross-functional teams to deliver high-quality software solutions. What’s required 6+ years of experience in full-stack application development. Proficiency in React, C#, ASP.NET , and SQL. Strong analytical and problem-solving skills with a focus on delivering robust solutions. Excellent attention to detail and commitment to quality. Effective communication and teamwork skills. High ethical standards and professionalism. Nice to have Experience with Node.js.

🏢 Summary: Full Stack Developer role focused on building and maintaining cloud-native, event-driven applications on Google Cloud Platform. The position involves developing scalable backend services with Python (FastAPI) and modern frontend applications with React and TypeScript. You will design high-performance APIs and integrate GCP services to deliver production-ready solutions. 🗂️ Requirements: Strong proficiency in Python and FastAPI, Experience with asynchronous programming, Hands-on experience with React and TypeScript, Experience with Google Cloud Platform services, Experience with event-driven architecture and Pub/Sub systems, Experience with Cloud Run, Cloud Functions, Cloud Storage, Experience with Docker and GCP-based CI/CD pipelines, Experience with relational and NoSQL databases, Knowledge of RPC-based integrations, Ability to design synchronous and asynchronous APIs, Polish language proficiency at B2 level 📃 Skills: Python, FastAPI, React, TypeScript, GCP, PubSub, CloudRun, CloudFunctions, CloudStorage, Docker, CICD, CloudSQL, Firestore, BigQuery, SQL, NoSQL, RPC, SDK 🏢 Description: We are looking for an experienced Full Stack Developer to join a team responsible for building and maintaining modern cloud-native applications based on event-driven architecture and Google Cloud Platform technologies. In this role, you will contribute to the design, development, and optimization of scalable backend services and user-facing applications. You will work closely with product, design, and platform engineering teams to deliver high-quality production-ready solutions. Key Responsibilities Design, develop, and maintain scalable web applications using Python (FastAPI) and React Build backend services leveraging Google Cloud Platform SDKs and RPC-based integrations Develop and maintain event-driven architectures using Google Cloud Pub/Sub and related messaging technologies Design and implement high-performance synchronous and asynchronous APIs Create intuitive and responsive user interfaces using React, TypeScript, and modern UI frameworks Collaborate with product, design, and platform teams to deliver new features and enhancements Participate in architecture discussions, code reviews, and technical design sessions Ensure high code quality through testing, automation, and CI/CD best practices Requirements Strong proficiency in Python, including FastAPI and asynchronous programming Experience working with Google Cloud SDKs and cloud-native development Hands-on experience with React, TypeScript, and component-based UI development Solid understanding of event-driven architectures and Pub/Sub messaging systems Experience with Google Cloud services such as Cloud Run, Pub/Sub, Cloud Functions, and Cloud Storage Familiarity with Docker and CI/CD pipelines within GCP environments Experience with relational and NoSQL databases such as Cloud SQL, Firestore, and BigQuery Strong troubleshooting, performance optimization, and observability skills Excellent communication and collaboration skills, with experience working in distributed teams Polish B2 +

🏢 Summary: Full Stack Developer role focused on building scalable, cloud-native applications using React and C# .NET Core in a capital markets environment. The position involves developing microservices, REST APIs, data pipelines, and analytical solutions supporting credit and market risk domains. 100% remote B2B contract with flexible start date. 🗂️ Requirements: 4-5+ years of full stack development experience, Strong expertise in React, Strong expertise in C#, Experience with .NET Core, Experience with microservices architecture, Experience with event-driven architecture, Experience with distributed systems, Experience building REST APIs, Hands-on experience with Python, Experience with PySpark, Experience with Power BI, Experience with data modeling, Experience in credit risk and market risk domains 📃 Skills: React, C#, .NETCore, Microservices, REST, TypeScript, Python, PySpark, PowerBI, DataModeling, DistributedSystems, EventDriven, Cloud 🏢 Description: Start Date: ASAP / Within 1 Month / Flexible Work Model: 100% remote Contract Type: B2B (140-160 PLN/h + VAT) We are looking for a highly skilled Full Stack Developer with deep expertise in React for frontend development and C# .NET Core for backend services. This role requires hands‑on experience building scalable, cloud‑native systems, along with strong exposure to capital markets, especially within credit risk and market risk domains. Expectations Minimum 4-5 years of professional software development experience across frontend and backend technologies. Strong expertise in React, C# .NET Core , microservices, event‑driven architecture, and distributed systems. Hands‑on experience with Python (pyspark), Power BI dashboards, data modeling, and analytical reporting. Responsibilities Develop and maintain full stack applications using React, C# .NET Core, and modern cloud‑native technologies. Build scalable backend services, REST APIs, and microservices with a focus on performance and resilience. Implement modular, accessible, and high‑quality frontend components using React and TypeScript. Collaborate with business and risk experts to deliver solutions in credit risk, market risk, and capital markets workflows. Work with Python (pyspark) to build data pipelines, transformations, and analytics processes. What We Offer Medicover healthcare package Multisport card Access to an e-learning platform Group life insurance