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/CD

Hays 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 contract

Start date: November-December 2026

Project duration: 12 months with the possibility of extension (long-term initiative)

Rate: 150-200 PLN/h (net + VAT)

Experience: min. 8 years

Project 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+)
• HTML5
• CSS3 / Less
• REST APIs
• GitLab CI/CD
• Redux
• Automated UI testing
• Agentic LLM tools supporting software development

Scope of services:

• Develop and enhance large-scale frontend applications built with React
• Design and maintain reusable business component libraries used across multiple products
• Build data-driven user interfaces powered by backend APIs
• Co-design frontend-backend communication patterns and data flows
• Collaborate with backend engineers on API design and integration approaches
• Take ownership of styling, CSS implementation, and the overall visual quality of applications
• Address frontend performance challenges related to large datasets, pagination, loading strategies, and list virtualization
• Create and execute tests for UI functionalities
• Utilize AI-assisted development tools to support the software delivery process
• Contribute to technical decision-making and propose improvements to existing solutions

Required competencies:

• 8+ years of experience in React, proven track of engagement in long-term projects in React
• Expertise in HTML5 and JavaScript (ES).
• Experience with React 17+ and Redux is a plus.
• Experience in testing UI applications
• Proficiency in CSS3/Less (not being afraid to style applications).
• Clean coding skills.
• Excellent problem-solving abilities.
• Experience in RESTful API design
• Familiarity 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 process

Nice to have:

• Experience with Redux
• Experience with Cypress
• Experience with Figma
• Understanding of UX principles and best practices
• Experience with SASS or other CSS preprocessors
• Experience contributing to design systems or shared component libraries

Cooperation process:

• Profile and experience review by the Hays team
• A conversation with a Hays consultant about the project and scope of services
• A technical meeting with project representatives (up to 2 stages)
• Feedback and cooperation proposal
• Welcome 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.