Fullstack Developer (Node.js + React)

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