Senior Full-Stack Engineer (NodeJS + React)

🏢 Summary: Senior Full-Stack Engineer role focused on designing and evolving scalable SaaS systems using Node.js and React in a 100% remote B2B model. The position involves architectural decision-making, production system ownership, performance optimization, and mentoring within a distributed team. The offer targets experienced engineers capable of leading technical initiatives and ensuring system reliability at scale. 🗂️ Requirements: Minimum 10 years of professional software development experience, Proven experience with SaaS-based systems, Strong knowledge of scalable systems and software architecture, Hands-on experience with Node.js, Hands-on experience with React, Experience designing or evolving system architectures, Experience working with production systems and real users, Experience with monitoring, debugging, and performance optimization, Ability to own major system components and lead technical decisions, Excellent English proficiency 📃 Skills: Node.js, React, JavaScript, SaaS, AWS, GCP, Azure, CI/CD, DevOps, Architecture, Monitoring, Debugging, Performance, Scalability 🏢 Description: For a client, we are looking for a Senior Full-Stack Engineer (NodeJS + React)! Salary: 24 000-27 000 net+VAT B2B 100% remote RESPONSIBILITIES Architecture, production, and reliability experience: Proven experience designing systems from scratch or significantly evolving existing architectures Experience working on production systems with real users Strong understanding of architectural trade-offs (performance, scalability, cost, and maintainability) Experience with monitoring, debugging, and performance optimization in production environments Familiarity with handling production issues and incidents Ownership and leadership: Experience owning major system components or leading technical decisions Ability to work independently with minimal supervision Experience mentoring junior or mid-level developers and collaborating within a team REQUIREMENTS At least 10 years of professional software development experience Proven experience working with SaaS-based systems Strong understanding of scalable systems and software architecture Hands-on experience with Node.js and React Excellent English proficiency and strong communication skills NICE TO HAVE Experience with cloud platforms such as AWS, GCP, or Azure Familiarity with CI/CD pipelines and modern DevOps practices Experience working in distributed or remote teams Product mindset — ability to understand business requirements and translate them into technical solution WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract and rate: 24 000-27 000 PLN/hour 100% remote work The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client. Events and integration meetings, as well as participation in various initiatives, e.g., sports. Access to the benefits offering (medical care, life insurance, Multisport card). WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch. DO YOU HAVE ANY QUESTIONS? Contact the recruiter responsible for this process directly. Iga Olszewska-Magnowska Senior IT Delivery Consultant iga.olszewska@speedapp.pl

🏢 Summary: Senior Frontend Developer role focused on building and maintaining complex cloud-based web applications for network configuration, monitoring, and optimization. The position involves developing new features, maintaining a custom UI component library, and contributing to code and UX reviews within a global team. Hybrid work model with long-term B2B cooperation. 🗂️ Requirements: 5+ years experience building complex web applications, Strong knowledge of JavaScript, Strong knowledge of TypeScript, Strong knowledge of HTML5, Strong knowledge of CSS3, Experience with React, Experience with Redux, Experience with Redux Toolkit, Experience writing well-tested maintainable code, Experience with REST API integration, Proficient English communication skills 📃 Skills: JavaScript, TypeScript, HTML5, CSS3, React, Redux, ReduxToolkit, REST, Cypress, ReactTestingLibrary, Webpack, Lerna, Storybook, Cytoscape, ChartJS, MapLibre 🏢 Description: For a client, we are looking for a Senior Frontend Developer Salary: 150-170 net+VAT B2B Hybrid model: 1 day per week from the office in Warsaw or Kraków RESPONSIBILITIES About our Team As a team member, you will have the possibility to participate in the whole development process in Network Cloud Team projects. The primary objective of our applications is to set up, configure, monitor, and optimize servers and networks for clients globally. Working in our team allows you to learn various network automation techniques, be part of and create a mobile network future, develop cloud-based applications and have a real impact on how it will look like. Role and Responsibilities Develop new features, as well as maintain existing ones. Implementation and maintenance of custom UI components library. Participate in code review, as well as UX design review. Cooperation with colleagues from other Centers around the world. REQUIREMENTS 5+ years of experience building complex web applications using JavaScript, TypeScript, HTML5, CSS3. Experience with React, Redux and Redux Toolkit; Familiarity writing well-tested, maintainable code (knowledge of Cypress.io and React Testing Library is a plus). Familiarity with REST API integration Proficient English communication skills. NICE TO HAVE Experience with Webpack; Experience with Lerna or other mono-repo solutions; Experience with Storybook and component libraries development; Experience with data visualization (knowledge of Cytoscape.js, react-chartjs-2, maplibre or similar libraries is a plus); WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract and rate: 150-170 PLN/hour Hybrid work from Warsaw or Cracow (1 times a week in the office) The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client. Events and integration meetings, as well as participation in various initiatives, e.g., sports. Access to the benefits offering (medical care, life insurance, Multisport card). WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch. DO YOU HAVE ANY QUESTIONS? Contact the recruiter responsible for this process directly. Iga Olszewska-Magnowska Senior IT Delivery Consultant iga.olszewska@speedapp.pl

🏢 Summary: B2B contract role for a Senior Full-Stack Engineer to build and own features end-to-end, from Java/Spring backend services and data models to React-based frontend interfaces. The position involves contributing to shared UI components and backend architecture, performing cross-stack code reviews, and working in a cloud-native environment. 🗂️ Requirements: Strong backend experience with Java 21, Proficiency in Spring and Spring Boot, Experience with Hibernate, Solid frontend experience with JavaScript and TypeScript, Strong knowledge of React and Redux Toolkit, Good understanding of relational databases, especially MariaDB, User-level or higher Linux skills, Confident use of Git workflows, Ability to write well-tested, maintainable code, Advanced technical English, Experience with Kubernetes and cloud-native platforms, Ability to effectively use AI coding assistants and LLM tools 📃 Skills: Java, Spring, SpringBoot, Hibernate, JavaScript, TypeScript, React, Redux, MariaDB, SQL, Linux, Git, Kubernetes, AI, LLM 🏢 Description: Join our client's team as a Senior Full-Stack Engineer! RESPONSIBILITIES Own features end-to-end — from API and data model on the backend to the UI on the frontend Build and maintain backend services in Java, and rich interfaces in React Contribute to our shared UI component library and backend architecture alike Take part in code reviews across the stack — backend, frontend, and the glue in between REQUIREMENTS Strong backend skills in Java 21 with Spring / Spring Boot and Hibernate Solid frontend experience with JavaScript, TypeScript, React, and Redux Toolkit Good grasp of relational databases, especially MariaDB Linux skills at user level or above, plus confident Git workflows You write well-tested, maintainable code on both sides of the stack Advanced technical English for design, review, and documentation\ Proven experience with cloud-native platforms such as Kubernetes Comfortable using AI tools (coding assistants, LLMs) as part of your daily workflow — and the judgment to know when to trust them and when to think for yourself NICE TO HAVE Experience building software for telecommunication systems Knowledge of protocols like IPv4/6, DNS, BGP, DHCP, SR, and ZTP Data visualization libraries — Cytoscape.js, react-chartjs-2, MapLibre, or similar Storybook, mono-repo tooling (Lerna), or Webpack experience Automation tools such as Ansible or Terraform Understanding of Linux and Kubernetes networking (routing, iptables, CNI) WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract and rate: 160-180 PLN/hour Hybrid work from Kraków (1 times a week in the office) The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client Events and integration meetings, as well as participation in various initiatives, e.g., sports Access to the benefits offering (medical care, Multisport card) WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch. DO YOU HAVE ANY QUESTIONS? Contact the recruiter responsible for this process directly. Karolina Kizowska Senior IT Delivery Consultant karolina.kizowska@speedapp.pl +48 608 487 448

🏢 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: B2B contract role for a Senior Frontend Developer to architect and build advanced single-page applications in the banking domain. The position focuses on frontend architecture, performance optimization, and integration with backend services using modern web technologies. Hybrid work model with collaboration across cross-functional teams. 🗂️ Requirements: Strong experience with HTML, Strong experience with CSS, Strong experience with JavaScript, Strong experience with TypeScript, Hands-on experience with Web Components, Hands-on experience with Lit, Good knowledge of Node.js, Knowledge of npm ecosystem, Experience with Vitest or similar testing frameworks, Experience integrating REST APIs, Experience integrating GraphQL APIs 📃 Skills: HTML, CSS, JavaScript, TypeScript, WebComponents, Lit, Node.js, npm, Vitest, REST, GraphQL 🏢 Description: We are looking for a Senior Frontend Developer for our client in the banking industry RESPONSIBILITIES Architect and implement advanced user interfaces and single-page applications using TypeScript and JavaScript Define and promote best practices for frontend architecture, state management and reusable components Optimize application performance, including load times and Core Web Vitals, ensuring smooth user experience across devices Collaborate closely with backend developers, UX/UI designers, and product managers Integrate frontend applications with REST and GraphQL APIs Ensure code quality through testing and participation in development lifecycle processes REQUIREMENTS Strong experience with HTML, CSS, JavaScript, and TypeScript Hands-on experience with Web Components / Lit Good knowledge of Node.js and npm ecosystem Experience with testing frameworks such as Vitest NICE TO HAVE Experience with CI/CD pipelines Familiarity with Kafka Knowledge of NinjaFork Experience working with messaging systems (MQ) WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract and rate: 110-120 PLN/hour Hybrid work from Warsaw / Łódź / Gdynia / Gdańsk (3 times a week in the office) The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client Events and integration meetings, as well as participation in various initiatives, e.g., sports Access to the benefits offering (medical care, Multisport card) WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch.

🏢 Summary: Seeking an experienced Mobile Engineer to build and iterate on a React Native-based mobile platform in the legal tech industry, focused on simplifying access to legal services. The role involves close collaboration with product teams to design, develop, and optimize mobile applications published on app stores. This is a fully remote B2B opportunity for a senior-level developer. 🗂️ Requirements: BSc in Computer Science or related field, Minimum 5 years of experience in JavaScript, Minimum 5 years of experience in React Native, Experience with GraphQL, Experience with Node, Experience with automated testing frameworks, Experience delivering apps to App Store or Google Play 📃 Skills: JavaScript, ReactNative, GraphQL, Node, Testing, iOS, Android 🏢 Description: Join the client's team in the legal tech industry and help build a mobile platform that simplifies access to legal services during key life events. RESPONSIBILITIES We are looking for an experienced Mobile Engineer who is passionate about technology, is capable of breaking down complex problems, and has a strong will to get things done. You will be part of the team working closely with product and various functions in the company to rapidly iterate on our product and find the best solutions. Join us as we disrupt the legal services industry, if you want to apply your coding and tech design skills to make a significant positive impact on people during their key life events. REQUIREMENTS BSc in Computer Science, Software Engineering or related field At least 5 years of experience in JavaScript, React Native – a must Experience with GraphQL Experience with Node Experienced with automatic testing frameworks Developing apps that are currently in the App Store or Google Play WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract. 100% remote work. The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client. Events and integration meetings, as well as participation in various initiatives, e.g., sports. Access to the benefits offering (medical care, life insurance, Multisport card). WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch.

🏢 Summary: B2B contract role for a Senior Mobile Engineer to develop and scale a high-traffic React Native mobile application used internationally. The position involves owning features end-to-end, contributing to architecture decisions, and collaborating closely with backend teams. The focus is on building performant, stable, and well-tested iOS and Android apps. 🗂️ Requirements: 4+ years of professional experience with React Native, Strong knowledge of iOS and Android platforms, Experience with app releases and distribution, Solid understanding of mobile architecture and design patterns, Experience with automated testing, Very good English communication skills, Working proficiency in Polish 📃 Skills: ReactNative, iOS, Android, JavaScript, MobileArchitecture, DesignPatterns, AutomatedTesting, AppStore, GooglePlay, English, Polish 🏢 Description: Senior Mobile Engineer (React Native) Location: Remote Contract: B2B Salary: up to 30 000 PLN net / month About the company A product-focused technology company developing a mobile and web platform that supports educational institutions and families in their daily operations. The product simplifies communication, reduces administrative work, and is used at scale by a large and growing international user base. Role overview The company is looking for an experienced Senior Mobile Engineer (React Native) to help develop and scale a high-traffic mobile application. You will work on core product features, contribute to architectural decisions, and collaborate closely with backend and product teams. Responsibilities Develop and maintain a large-scale React Native mobile app (iOS & Android) Own features from concept to production Collaborate with backend engineers on new functionality Write clean, maintainable, and well-tested code Contribute to architectural and technical decisions Optimize performance, stability, and developer experience Requirements 4+ years of professional experience with React Native Strong knowledge of iOS and Android platforms Experience with app releases and distribution Solid understanding of mobile architecture and design patterns Experience with automated testing Very good English communication skills Working proficiency in Polish Nice to have Experience with Firebase Knowledge of mobile analytics tools Advanced testing experience Familiarity with the JavaScript ecosystem (Node.js, React, Next.js) Understanding of mobile UI/UX principles What’s offered 30 000 PLN net monthly (B2B) 20–26 days of paid time off Modern equipment and tools Benefits package (sports card, private healthcare, English lessons) High autonomy and real impact on product and technical decisions Transparent culture with no micromanagement

🏢 Summary: Full-time Senior Back-End Engineer (Node.js) role focused on designing and maintaining scalable, high-performance server-side applications and APIs for modern, data-driven platforms. The position involves building RESTful services, integrating with third-party systems, ensuring code quality through testing, and optimizing system reliability and performance. Hybrid work model in Warsaw with B2B or CoE contract options. 🗂️ Requirements: Strong experience with Node.js, Strong experience with Express.js, Experience building and integrating APIs (GraphQL or REST), Knowledge of OAuth, JWT, and session-based authentication, Experience with MySQL, Experience with PostgreSQL, Experience writing unit tests with Chai and Mocha, Experience using Git and version control systems 📃 Skills: Node.js, Express.js, GraphQL, REST, OAuth, JWT, MySQL, PostgreSQL, Chai, Mocha, Git 🏢 Description: Senior Back-End Engineer (Node.js) 💰 Salary: 18,700-20,900 PLN/Month 💻 Warsaw, Poland (Hybrid - 3 days in office, 2 days remote) 🕦 Full-time ☑️ B2B or CoE We’re looking for a Senior Back-End Engineer 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: 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). Strong experience with databases such as MySQL and  PostgreSQL. Experience writing unit tests with tools such as Chai and Mocha. Strong experience using Git and version control systems. Proficiency in English (both written and spoken). Nice To have: Bachelor’s degree in Computer Science or a related field. Experience with cloud platforms (AWS, Azure, or GCP), as well as containerization and orchestration tools such as Docker and Kubernetes. Experience with microservices architecture. Experience setting up CI for static analysis and test execution. Experience developing RAG applications and storing data in vector embeddings. Key Responsibilities: Design, build, and maintain scalable, high-performance server-side applications and RESTful APIs using Node.js and Express.js. Guide and supervise the development of key code components to ensure long-term reliability and scalability. Integrate with front-end components and third-party services. Actively review the codebase, recommending and implementing refinements where needed. 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: 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

🏢 Summary: Senior Java Developer role involving full-cycle development from requirements and architecture to implementation and testing, with a focus on building and maintaining Java-based systems in cloud environments. The position includes developing new functionalities, maintaining existing code, and working with modern frameworks and containerized platforms. Hybrid B2B cooperation with competitive hourly rate and additional benefits. 🗂️ Requirements: Very good knowledge of Java 21, Experience with Hibernate, Experience with Spring, Experience with Spring Boot, Understanding of relational databases (MariaDB), Linux skills (user level or higher), Proficiency with Git, Advanced technical English, Experience with cloud-based architectures, Experience with Kubernetes, Comfortable using AI coding assistants and LLMs 📃 Skills: Java, Hibernate, Spring, SpringBoot, MariaDB, Linux, Git, Kubernetes, AI, LLM 🏢 Description: Join our client's team as a Senior Java Developer! RESPONSIBILITIES Participation in full development cycle: from requirements, specification up to architecture, development and system tests Implementation of new functionalities Maintenance of existing code REQUIREMENTS Very good knowledge of Java 21 Experience with Hibernate and Spring, Spring Boot frameworks Understanding relational databases, especially MariaDB Linux skills on user level or higher Knowledge and ability to work with version control system Git Advanced technical English skills Experience with cloud-based architectures and platforms such as Kubernetes Comfortable using AI tools (coding assistants, LLMs) as part of your daily workflow NICE TO HAVE Experience with making software for telecommunication systems Familiarity with concepts of SDN, Segment Routing, and OpenFlow Operational experience with enterprise-class routers and switches Knowledge of protocols such as IPv4/6, DNS, BGP, DHCP, SR and ZTP Knowledge of automation tools such as Ansible and Terraform Understanding of Linux and K8s networking (e.g. routing, iptables, CNI) WHAT DO WE OFFER ON THIS PROJECT? Cooperation based on a B2B contract and rate: 160-180 PLN/hour Hybrid work from Kraków or Warsaw (1 times a week in the office) The support of a dedicated mentor. In the relationship, we focus on direct communication. When you join speedapp, you will be put in touch with a dedicated mentor who will make sure that you enjoy working with us and with the client. Events and integration meetings, as well as participation in various initiatives, e.g., sports. Access to the benefits offering (medical care, Multisport card) WHAT DOES THE RECRUITMENT PROCESS LOOK LIKE? Application: Apply and submit your CV. After the application review, the recruiter will contact selected candidates by phone. Screening: Have a conversation with a speedapp recruiter about your experience. Next steps: The speedapp recruiter will explain the recruitment process for the specific position. The speedapp recruiter will stay in touch with you throughout the entire process. ABOUT SPEEDAPP At speedapp, we believe that an organization is only as good as the people who make it up. We are a team of IT experts and other professionals working for our clients around the world (including Israel, Austria, USA). We go far beyond the HR category. We build IT teams and also help manage them. 👉 10 years of experience 👉 +100 clients worldwide +300 hires per year 💎 We have won the prestigious "Forbes Diamonds" award four times (2022, 2023, 2024, 2025). We are a member of the European Fast Growth Icons network and FinTech Poland. We are ranked 18th among the 100 fastest growing companies 2023 by Clutch. DO YOU HAVE ANY QUESTIONS? Contact the recruiter responsible for this process directly. Karolina Kizowska Senior IT Delivery Consultant karolina.kizowska@speedapp.pl +48 608 487 448