B2B Project: Senior UI Developer

B2B | Large-scale data-driven UI development, AI-powered onboarding platform | React, CSS/LESS, REST API, component libraries, Azure, GitLab CI/CDHays Contracting Services operates under a B2B service delivery model. We are currently looking for a B2B contractor to provide services in the area of frontend engineering and user interface development as part of a long-term programme focused on customer onboarding solutions and business-critical digital platforms.

Location: Hybrid (3 days/week onsite in Kraków or Wrocław, 2 days remote)Cooperation type: B2B contractStart date: November-December 2026Project duration: 12 months with the possibility of extension (long-term initiative)Rate: 150-200 PLN/h (net + VAT)Experience: min. 8 yearsProject description:Our client is expanding a portfolio of large-scale UI applications supporting customer onboarding processes.

The team is responsible for developing data-driven user interfaces and a shared business component library used across multiple applications. New functionalities will also support processes leveraging data provided by AI-powered solutions.The initiative is at an early stage of its roadmap, offering an opportunity to contribute to the design and evolution of new frontend capabilities, reusable components, and integration patterns that will be adopted across multiple solutions. The scope includes both new feature development and shaping long-term frontend standards within a growing technology landscape.As a B2B contractor, you will collaborate with experienced, cross-functional project teams operating in a pod model, where delivery capabilities are brought together within a single project structure. The engagement focuses on enterprise-scale applications, complex business processes, and long-term product development rather than simple website or frontend maintenance activities.Technology environment:React 17+JavaScript (ES6+)HTML5CSS3 / LessREST APIsGitLab CI/CDReduxAutomated UI testingAgentic LLM tools supporting software developmentScope of services:Develop and enhance large-scale frontend applications built with ReactDesign and maintain reusable business component libraries used across multiple productsBuild data-driven user interfaces powered by backend APIsCo-design frontend-backend communication patterns and data flowsCollaborate with backend engineers on API design and integration approachesTake ownership of styling, CSS implementation, and the overall visual quality of applicationsAddress frontend performance challenges related to large datasets, pagination, loading strategies, and list virtualizationCreate and execute tests for UI functionalitiesUtilize AI-assisted development tools to support the software delivery processContribute to technical decision-making and propose improvements to existing solutionsRequired competencies:8+ years of experience in React, proven track of engagement in long-term projects in ReactExpertise in HTML5 and JavaScript (ES).Experience with React 17+ and Redux is a plus.Experience in testing UI applicationsProficiency in CSS3/Less (not being afraid to style applications).Clean coding skills.Excellent problem-solving abilities.Experience in RESTful API designFamiliarity with agile development practices (Scrum, Kanban, etc.).Good communication skills and the ability to clearly state requirements for the backend team.Experience working with CI/CD pipelines (e.g., GitLab CI/CD)Experience using agentic LLMs to support the development processNice to have:Experience with ReduxExperience with CypressExperience with FigmaUnderstanding of UX principles and best practicesExperience with SASS or other CSS preprocessorsExperience contributing to design systems or shared component librariesCooperation process:Profile and experience review by the Hays teamA conversation with a Hays consultant about the project and scope of servicesA technical meeting with project representatives (up to 2 stages)Feedback and cooperation proposalWelcome to the project!The cooperation is carried out between independent businesses (B2B model) and covers the performance of services within the agreed project scope. The Contractor independently organizes and manages the manner in which the services are performed, taking into account the project requirements, security obligations, and the necessary communication with the client. Any information regarding location, availability, or project meetings is provided solely for organizational purposes and shall not be construed as creating an employment relationship, employer-like supervision, or performance of work under the direction or control of the client.