Sr Full-stack Developer (React, Java)

🏢 Summary: B2B contract opportunity for a Full Stack Developer focused on Java, React, and cloud-native technologies to build advanced planning applications and scalable backend/frontend systems. The role involves AI-assisted development, CI/CD ownership, automated testing, and collaboration with cross-functional product teams in a mostly remote setup. 🗂️ Requirements: Strong proficiency in React, Strong proficiency in Next.js, Strong proficiency in Node.js, Experience with Server-Side Rendering (SSR), Advanced programming experience with Java, Advanced programming experience with TypeScript, Deep knowledge of Java enterprise development, Experience with Spring Boot, Experience integrating LLMs and AI tools, Experience with REST APIs, Experience with relational databases, Experience with NoSQL databases, Experience with MS Azure, Hands-on experience with Docker, Hands-on experience with Kubernetes, Hands-on experience with Terraform, Experience with GitHub Actions, Experience with Gradle, Experience writing Unit tests, Experience writing Integration tests, Experience writing E2E tests, English proficiency minimum B2, Polish proficiency minimum B2+, Understanding of Agile principles, Knowledge of Scrum or Kanban 📃 Skills: Java, React, Next.js, Node.js, TypeScript, JavaScript, Spring, SpringBoot, REST, SQL, NoSQL, Azure, Docker, Kubernetes, Terraform, GitHub, Actions, Gradle, SSR, LLM, AI, Scrum, Kanban 🏢 Description: For one of our clients, we are looking for a Full Stack Developer (Java,React). Offer • Rate: up to 140 PLN/h net+VAT • Location: remote + visits in Katowice once per quarter • Contract: B2B Requirements • Strong proficiency in React, Next.js, and Node.js , including Server-Side Rendering (SSR) . Vue is a plus. • Advanced, hands-on programming experience with both Java and TypeScript / JavaScript. • Deep knowledge of enterprise software development using Java and Spring Boot technologies. • Experience integrating LLMs and AI tools into daily workflows to optimize development speed. • Mastery of REST APIs and experience with r elational/NoSQL databases , especially within MS Azure . • Hands-on experience with Docker, Kubernetes, Terraform , and pipeline automation via GitHub Actions and Gradle. • Direct experience writing automated Unit, Integration, and E2E tests. • Proficiency in English at a B2 minimum level. • Proficiency in Polish at a B2+ minimum level. • Strong understanding of Agile principles including Scrum or Kanban. Responsibilities • Design advanced planning applications in close collaboration with cross-functional teams. • Develop robust backend APIs for resource scheduling, allocation logic, and core modules. • Create responsive interfaces focused on performance, security, data visualization, and accessibility. • Build your own AI-based work environment using advanced developer tools to maximize efficiency. • Manage the platform lifecycle from architectural strategy to operations and CI/CD practices. • Design and implement automated test scenarios to guarantee platform success. • Maintain active communication with the Technical Product Owner and Product Management organization to align priorities.

🏢 Summary: Full-time Senior Full Stack Developer role focused on building scalable, data-driven platforms for financial and enterprise sectors using Node.js and React. The position involves designing microservices, developing RESTful APIs, and creating responsive front-end applications in a hybrid work model (Warsaw). 🗂️ Requirements: 5+ years experience as Senior Full Stack Developer, Strong expertise in Node.js, Strong expertise in React, Experience with Express.js, Experience building RESTful or GraphQL APIs, Knowledge of OAuth and JWT authentication, Proficiency in Redux, HTML5, CSS3, ES6+, Experience with Vite, Webpack or Babel, Experience with MySQL or PostgreSQL, Experience with AWS, Azure or GCP, Experience with Docker and Kubernetes, Proficiency with Git 📃 Skills: Node.js, React, Express.js, GraphQL, REST, OAuth, JWT, Redux, HTML5, CSS3, JavaScript, ES6, Vite, Webpack, Babel, MySQL, PostgreSQL, AWS, Azure, GCP, Docker, Kubernetes, Git, SQL, MongoDB, CI/CD 🏢 Description: Senior Full Stack Developer (Node.js + React) 💰 Salary: 23,000-24,800 PLN/Month 💻 Warsaw, Poland (Hybrid - 3 days in office, 2 days remote) 🕦 Full-time ☑️ B2B or CoE We’re looking for a Senior Full-Stack Developer to join a fast-growing international tech company focused on building modern, data-driven platforms that power digital transformation in the financial and enterprise sectors. Requirements: 5+ years of experience as a Senior Full Stack Developer with significant expertise in Node.js and React. Strong experience in building server-side applications using Node.js and Express.js. Hands-on experience with API development and integration, particularly with GraphQL or RESTful services. Strong knowledge of authentication and authorization mechanisms (OAuth, JWT, session-based). Front-end proficiency in React.js, Redux, HTML5, CSS3, and modern JavaScript (ES6+). Familiarity with front-end build tools such as Vite, Webpack, and Babel. Strong experience with databases such as MySQL and  PostgreSQL. Experience with cloud platforms (AWS, Azure, or GCP), as well as containerization and orchestration tools such as Docker and Kubernetes. Strong experience using Git and version control systems. Proficiency in English (both written and spoken). Key Responsibilities: Design, build, and maintain scalable, high-performance server-side applications and RESTful APIs using Node.js and Express.js. Develop and maintain interactive, responsive user interfaces using React.js, Redux, and modern JavaScript (ES6+). Lead the design and implementation of scalable architectures and microservices. Work closely with database engineers to design efficient schemas and manage data interactions using SQL databases or MongoDB. Ensure reliable deployments and smooth release of updates using CI/CD pipelines and Docker. Write unit and integration tests and optimize performance to ensure high-quality code. Collaborate closely with cross-functional teams to define and implement technical solutions. Improve system performance, reliability, and long-term maintainability through optimization and best practices. Get to know DevsData: We are a technology consulting company and a recruitment agency, delivering software solutions to clients from Europe and the US. We work 100% remotely, in an international team, including people from Asia, London, or San Francisco. We employ people with experience in international corporations as well as students of the best technical and business universities. Find out more: https://devsdata.com/

🏢 Summary: Full-stack Java developer role in the financial sector focused on building scalable microservices and modern frontend applications in an Agile environment. The position involves backend and frontend development using Java, Angular, cloud-native technologies, and distributed systems integrations. Hybrid work model with a long-term international project and competitive B2B rate. 🗂️ Requirements: 5+ years of commercial Java development experience, 2+ years of Angular experience, Knowledge of Spring Framework, Experience with microservices architecture, Experience with Docker, Experience with Kubernetes, Experience with Kafka and distributed systems, Knowledge of REST APIs, Knowledge of SQL, Experience with Oracle databases, Experience with Git, Understanding of Clean Code principles, Understanding of Continuous Integration, Experience integrating REST and SOAP services, Knowledge of XML, Knowledge of JSON, Knowledge of Avro, English level B2 or higher 📃 Skills: Java, Angular, React, Spring, Docker, Kubernetes, Kafka, REST, SQL, Oracle, Git, SOAP, XML, JSON, Avro, Jenkins, ArgoCD 🏢 Description: Senior Java Full-stack Developer 📍 Location: Warsaw, Gdańsk or Gdynia 🏢 Work model: Hybrid (3 days per week in the office) 📅 Project duration: August 2026 – January 2027 💰 B2B rate: up to 157 PLN/h ⏰ Full-time (40h/week) About the project Join an international financial institution and become part of a team responsible for building modern, scalable solutions supporting one of the company's key business domains. You will work in an Agile environment, developing cloud-ready microservices and integrating modern applications with existing enterprise platforms. This role combines backend and frontend development while giving you the opportunity to work with modern technologies, distributed systems, and high-performance applications. Your responsibilities Design, develop and maintain full-stack applications. Build and enhance Java-based microservices. Develop modern frontend solutions using Angular. Integrate applications using REST APIs, Kafka, MQ and Oracle databases. Participate in migration and transformation of existing systems. Ensure application quality, scalability and performance. Collaborate with architects, analysts, QA engineers and business stakeholders. Contribute to code reviews and technical improvements. We are looking for someone who has Minimum 5 years of commercial experience with Java development. At least 2 years of experience with Angular (React is also valued). Strong knowledge of Spring Framework . Experience building microservices architectures . Practical experience with Docker and Kubernetes . Experience working with Kafka and distributed systems. Knowledge of REST APIs , SQL and Oracle databases. Experience with Git . Understanding of Clean Code , Continuous Integration and software engineering best practices. Experience integrating REST and SOAP services. Good understanding of XML, JSON and Avro . Good command of English (B2 or higher) . Nice to have Jenkins Argo CD Event Sourcing Schema Registry DevOps practices What we offer Competitive B2B rate of up to 157 PLN/hour . Long-term international project. Opportunity to work with modern cloud-native technologies. Challenging projects within the financial sector. Professional, collaborative and Agile environment. Work with experienced engineers on large-scale enterprise solutions.

🏢 Summary: Oferta dotyczy długofalowej współpracy B2B na stanowisku Fullstack Developer (Java + React) w 100% zdalnym modelu pracy. Rola obejmuje projektowanie i rozwój nowych funkcjonalności, utrzymanie oraz optymalizację istniejących rozwiązań w architekturze fullstack z naciskiem na jakość kodu i pracę w Agile. Projekt wymaga silnych kompetencji backendowych w Java oraz frontendowych w React i nowoczesnym JavaScript/TypeScript. 🗂️ Requirements: Minimum 5 lat doświadczenia komercyjnego, Doświadczenie w projektowaniu stabilnych i skalowalnych rozwiązań w Java, Doświadczenie w tworzeniu aplikacji klienckich w React, Bardzo dobra znajomość JavaScript, Bardzo dobra znajomość TypeScript, Doświadczenie w pracy w metodykach Agile (Scrum lub Kanban) 📃 Skills: Java, React, JavaScript, TypeScript, Agile, Scrum, Kanban, Docker, Git, Jira, Confluence, Cypress 🏢 Description: Stanowisko: Fullstack Developer (Java + React) Start: Asap Wymiar pracy: Pełen etat Miejsce pracy: 100 % zdalnie Forma współpracy: B2B z ITFS, współpraca długofalowa Stawka: 140-180 PLN/h + VAT Zadania: ·        Projektowanie i wdrażanie nowych funkcjonalności w architekturze Fullstack (Java + React). ·        Utrzymywanie, optymalizacja oraz refaktoryzacja istniejącej bazy kodu w celu podniesienia jej stabilności. ·        Aktywny udział w zwinnych procesach wytwórczych i ceremoniach zespołowych (Scrum/Kanban). ·        Zapewnianie wysokiej jakości oprogramowania poprzez regularne sesje Code Review oraz pisanie testów. ·        Bliska współpraca z zespołem i stroną biznesową w celu dostarczania rozwiązań precyzyjnie dopasowanych do wymagań. Wymagania: ·        Min. 5 lat doświadczenia ·        Projektowanie stabilnych i skalowalnych rozwiązań po stronie serwera w języku Java ·        Tworzenie intuicyjnych i wydajnych aplikacji klienckich z wykorzystaniem biblioteki React ·        Swobodne poruszanie się w nowoczesnych standardach języków JavaScript oraz TypeScript ·        Efektywne dostarczanie oprogramowania w zwinnych cyklach deweloperskich (Agile, Scrum, Kanban) Mile widziane: ·        Znajomość narzędzi CI/CD (np. Docker, GIT). ·        Doświadczenie w pracy z narzędziami do zarządzania zadaniami (Jira/Confluence). ·        Znajomość narzędzi do testowania (np. Cypress). Oferujemy: ·        Przejrzyste warunki współpracy w firmie o pewnej i stabilnej pozycji rynkowej ·        Możliwość skorzystania z dodatkowych benefitów (pakiet medyczny, sportowy, darmowa opieka księgowa - do 3 wpisów miesięcznie) P3422

🏢 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

🏢 Summary: Senior Full-stack Developer role focused on building and enhancing scalable digital banking solutions using React.js and Java. The position involves end-to-end development, automated testing, deployment, and ensuring quality, security, and reliability of applications in a hybrid work model. You will contribute to engineering practices, observability, and continuous improvement within a fast-paced environment. 🗂️ Requirements: Strong knowledge of React.js, Ability to write custom hooks, Experience building responsive reusable components, Strong knowledge of JavaScript, Strong knowledge of CSS, Strong knowledge of HTML, Proven experience with Java, Proven experience with Spring, Experience with GitLab CI/CD, Experience with Jest, Experience with React Testing Library, Experience with Playwright 📃 Skills: React, Java, JavaScript, CSS, HTML, Spring, GitLab, CI/CD, Jest, Playwright 🏢 Description: We are seeking a talented Senior Full-stack Developer with expertise in React.js and Java to join our dynamic team on an exciting project in the banking sector. If you are passionate about building robust, scalable applications and eager to contribute to a fast-paced, innovative environment, this opportunity may be an excellent fit for you. Please note that hybrid work, with 3 days from the Client office in Wroclaw, is possible. Responsibilities Help design, develop, and improve the digital product Apply a broad range of software engineering practices, from analyzing user needs and developing new features to automated testing and deployment Ensure the quality, security, reliability, and compliance of our solutions by applying our digital principles and implementing both functional and non-functional requirements Build observability into our solutions, monitor production health, help to resolve incidents, and remediate the root cause of risks and issues Share knowledge and expertise with colleagues and contribute regularly to our engineering culture and internal communities Requirements Thorough understanding of React.js and with an ability to write custom hooks and responsive reusable components In-depth knowledge of JavaScript, CSS, HTML, and front-end languages Proven experience in Java and Spring Knowledge of GitLab CI/CD Knowledge of testing frameworks, including Jest and React Testing Library, Playwright Nice to have Knowledge of Microsoft Azure, Terraform Working experience in Agile methodologies (Scrum, Kanban) and knowledge of associated tools like JIRA or GitLab boards We offer/Benefits We gather like-minded people: Engineering community of industry professionals Friendly team and enjoyable working environment Flexible schedule and opportunity to work remotely within Poland Chance to work abroad for up to 60 days annually Business-driven relocation opportunities We provide growth opportunities: Outstanding career roadmap Leadership development, career advising, soft skills, and well-being programs Certification (GCP, Azure, AWS) Unlimited access to LinkedIn Learning, Get Abstract, Cloud Guru English classes We cover it all: Stable income (Employment Contract or B2B) Participation in the Employee Stock Purchase Plan Benefits package (health insurance, multisport, shopping vouchers) Strategically located offices featuring entertainment and relaxation zones, table tennis and football, free snacks, fantastic coffee, and more Referral bonuses Corporate, social and well-being events Please, note: The set of bonuses might vary based on the role you apply for – specifics will be discussed with our recruiter during the general interview. We will reach out to selected candidates exclusively. EPAM is a leading global provider of digital platform engineering and development services. We are committed to having a positive impact on our customers, our employees, and our communities. We embrace a dynamic and inclusive culture. Here you will collaborate with multi-national teams, contribute to a myriad of innovative projects that deliver the most creative and cutting-edge solutions, and have an opportunity to continuously learn and grow. No matter where you are located, you will join a dedicated, creative, and diverse community that will help you discover your fullest potential.

🏢 Summary: Senior Full-stack Developer role focused on building and enhancing a digital banking product using React.js and Java. The position involves end-to-end development, quality assurance, observability, and production support in a hybrid work model. Ideal for engineers experienced in scalable applications, CI/CD, testing frameworks, and AI-driven solutions. 🗂️ Requirements: Strong knowledge of React.js with ability to write custom hooks and reusable responsive components, In-depth knowledge of JavaScript, CSS, HTML, Proven experience with Java and Spring, Experience with GitLab CI/CD, Experience with testing frameworks (Jest, React Testing Library, Playwright), Proven AI experience 📃 Skills: React, Java, JavaScript, Spring, HTML, CSS, GitLab, CI/CD, Jest, Playwright, Azure, Terraform, AI 🏢 Description: We are seeking a talented Senior Full-stack Developer with expertise in React.js and Java to join our dynamic team on an exciting project in the banking sector. If you are passionate about building robust, scalable applications and eager to contribute to a fast-paced, innovative environment, this opportunity may be an excellent fit for you. Please note that hybrid work, with 3 days from the Client office in Wroclaw, is possible. Responsibilities Help design, develop, and improve the digital product Apply a broad range of software engineering practices, from analyzing user needs and developing new features to automated testing and deployment Ensure the quality, security, reliability, and compliance of our solutions by applying our digital principles and implementing both functional and non-functional requirements Build observability into our solutions, monitor production health, help to resolve incidents, and remediate the root cause of risks and issues Share knowledge and expertise with colleagues and contribute regularly to our engineering culture and internal communities Requirements Thorough understanding of React.js and with an ability to write custom hooks and responsive reusable components In-depth knowledge of JavaScript, CSS, HTML, and front-end languages Proven experience in Java and Spring Knowledge of GitLab CI/CD Knowledge of testing frameworks, including Jest and React Testing Library, Playwright Proven AI experience Nice to have Knowledge of Microsoft Azure, Terraform Working experience in Agile methodologies (Scrum, Kanban) and knowledge of associated tools like JIRA or GitLab boards We offer We gather like-minded people: Engineering community of industry professionals Friendly team and enjoyable working environment Flexible schedule and opportunity to work remotely within Poland Chance to work abroad for up to 60 days annually Business-driven relocation opportunities We provide growth opportunities: Outstanding career roadmap Leadership development, career advising, soft skills, and well-being programs Certification (GCP, Azure, AWS) Unlimited access to LinkedIn Learning, Get Abstract, Cloud Guru English classes We cover it all: Stable income (Employment Contract or B2B) Participation in the Employee Stock Purchase Plan Benefits package (health insurance, multisport, shopping vouchers) Strategically located offices featuring entertainment and relaxation zones, table tennis and football, free snacks, fantastic coffee, and more Referral bonuses Corporate, social and well-being events Please, note: The set of bonuses might vary based on the role you apply for – specifics will be discussed with our recruiter during the general interview. We will reach out to selected candidates exclusively. EPAM is a leading global provider of digital platform engineering and development services. We are committed to having a positive impact on our customers, our employees, and our communities. We embrace a dynamic and inclusive culture. Here you will collaborate with multi-national teams, contribute to a myriad of innovative projects that deliver the most creative and cutting-edge solutions, and have an opportunity to continuously learn and grow. No matter where you are located, you will join a dedicated, creative, and diverse community that will help you discover your fullest potential.

🏢 Summary: B2B FullStack Developer role focused on building and enhancing a Client Onboarding platform for Global Banking and Markets using Java and React in a hybrid Kraków-based environment. The position involves developing REST APIs, working with microservices, improving system performance and security, and supporting production systems. Candidates will collaborate in a fast-paced DevOps-oriented team delivering innovative onboarding solutions. 🗂️ Requirements: Java 8+, React, Microservices, REST APIs, Testing, CI/CD, Debugging, Security awareness, Database schema design, PostgreSQL, DevOps, Problem-solving, Analytical skills, Collaborative environment experience 📃 Skills: Java, React, REST, Microservices, CI/CD, PostgreSQL, DevOps, Testing, Security 🏢 Description: As a FullStack Developer in our Kraków office, you will contribute to the development of a user-friendly Client Onboarding experience for Global Banking and Markets. This role emphasizes innovative thinking and a commitment to improving client experiences through technology. Work model: Hybrid (6 times per month work from office-Cracow) Business trips: n/a Start: ASAP/ one month notice period Assignment type: B2B Budget: 150-190 zł/h Main Responsibilities: Develop and maintain the Client Onboarding solution using Java and React. Debug existing code and extend functionality where necessary. Implement REST APIs in line with microservice architecture. Create and execute tests to ensure the reliability of functionalities and endpoints. Participate in performance and stability improvement initiatives. Contribute to security implementations around services and endpoints. Engage in production support as part of a rotating schedule. Key Requirements: Strong knowledge of Java 8+ / 18+ Proficient in React JS Ability to understand and debug existing code Experience with microservice architecture Experience with writing REST APIs Skill in writing tests to verify code functionality Familiarity with CI/CD tooling Strong security awareness in development practices Self-motivated with rapid learning capabilities Experience in a collaborative and fast-paced environment Strong problem-solving and analytical skills Good understanding of database schema design; knowledge of PostgreSQL is a plus Able to work in a DevOps environment Nice to Have: Familiar with DevOps practices Experience with cloud platforms Other Details: This position is based in Kraków, requiring hybrid work with meetings held online. The role involves substantial collaboration on innovative solutions aimed at enhancing the client onboarding process. Regular coding interviews will be conducted to assess coding skills.

🏢 Summary: Senior Full Stack Engineer role focused on building and optimizing React/TypeScript frontends and ASP.NET Core backend services supporting treasury workflows. The position involves designing scalable REST APIs, improving performance across the stack, and working with large datasets in production systems. Hybrid work model in Warsaw with strong emphasis on engineering best practices and reliability. 🗂️ Requirements: 5+ years of experience building production systems, Strong experience with C# and .NET ecosystem, Strong experience with ASP.NET Core, Strong experience with React, Strong experience with TypeScript, Experience designing and building REST APIs, Experience handling large datasets efficiently, Hands-on experience with ag-Grid, Highcharts or similar libraries, Understanding of authentication and authorization mechanisms, Experience with relational databases, Experience with performance optimization 📃 Skills: C#, .NET, ASP.NETCore, React, TypeScript, REST, ag-Grid, Highcharts, SQL, CI/CD, Authentication, Authorization, Serialization 🏢 Description: Senior Full Stack Engineer (.NET / React) Warsaw, hybrid, 3 days per week from the office. Responsibilities Build and enhance frontend applications and backend services supporting treasury workflows. Develop React/TypeScript single‑page applications and reusable UI components. Design and implement ASP.NET Core REST APIs with scalable pagination and filtering models. Optimize performance across the stack, including APIs, serialization, rendering, and large data grids. Collaborate with business stakeholders, quant teams, and product managers to deliver user‑focused solutions. Drive engineering best practices including code reviews, testing, CI/CD, and production support. Investigate production issues and improve observability and platform reliability. Mentor engineers and contribute to technical growth within the Warsaw team. Requirements 5+ years of software engineering experience building production systems. Strong experience with C#/.NET ecosystem and ASP.NET Core . Strong frontend experience with React and TypeScript. Experience building REST APIs and handling large datasets efficiently. Hands‑on experience with ag‑Grid, Highcharts, or similar UI/data visualization libraries. Strong understanding of authentication, authorization, and serialization mechanisms. Experience working with relational databases and performance optimization. Strong communication skills and ability to work directly with business stakeholders. Nice to Have Experience in treasury, trading, or financial systems. Strong product mindset and UX awareness.

🏢 Summary: Senior Fullstack Developer role focused on extending a HubSpot-based CRM with new frontend, backend, and integration functionalities in a fully remote setup. The position involves building custom modules, managing license and trial features, and ensuring reliable integrations between internal and external systems. The developer will take ownership of data flows, webhooks, and system reliability within a small cross-functional team. 🗂️ Requirements: Minimum 5 years of experience as Fullstack Developer, Strong knowledge of React, Strong knowledge of TypeScript, Solid experience with Node.js, Experience with API development, Hands-on experience with webhooks, Experience with system integrations, Ability to extend existing backend codebases, Experience with AI-assisted coding tools, English C1 level, Polish B2 level 📃 Skills: React, TypeScript, Node.js, APIs, Webhooks, HubSpot, CRM, LMS, Authentication, Integrations, Monitoring, Observability, Claude 🏢 Description: Senior Fullstack Developer (React / Node.js) – Fully Remote Location: Fully remote Working hours: 10:00–18:00 (UK time), no travel required Rate: PLN 120–160 / hour Project duration: Initial 2 months, extension very likely Client: International financial institution Process: 2 interview stages Team: 2 Developers, Project Manager, Architect About the Role We are looking for an experienced Senior Fullstack Developer to join a small, cross-functional team working on the expansion of an existing CRM system. The project focuses on extending a HubSpot-based solution with new frontend, backend, and integration functionalities. You will play a key role in designing and building a new custom HubSpot application for internal users, developing license and trial management features, and integrating multiple internal and external systems. The role combines hands-on development with ownership of integrations and data flow reliability. Responsibilities Design and develop a new custom module within an existing HubSpot application Build user-facing interfaces for internal HubSpot users Implement a management panel for customer trials and licenses Integrate the application with existing internal APIs Identify and implement missing backend functionalities Develop integration code in Node.js connecting LMS webhooks with the authentication system Automate user account creation based on LMS-triggered events Automate user roles and permissions assignment based on learning system data Ensure data consistency, reliability, and observability across systems Handle error management, retries, and monitoring of webhook-based flows Requirements Minimum 5 years of professional experience as a Fullstack Developer Very strong knowledge of React and TypeScript Solid experience with Node.js and API development Hands-on experience with webhooks and system integrations Ability to read, understand, and extend existing backend codebases Practical experience using Claude Code or similar AI-assisted coding tools English proficiency at C1 level (daily collaboration with international clients) Polish proficiency at B2 level or higher (internal team communication) What We Offer Fully remote work Competitive hourly rate: PLN 120–160 Sports card (Multisport or equivalent) Private medical healthcare Access to learning and training platforms Small, experienced team with a clear technical direction High likelihood of project extension after 2 months