Frontend Developer - React & UX

Job Title: Frontend Developer React & UX Location: Wilrijk, Belgium (Hybrid) Language: English Duration: 01/10/2026 – 31/03/2027 + Possibility of Extension Role Description: Context: SMARTLINK is the client connectivity and monitoring platform for compressed air installations. The SMARTLINK customer portal is where a fleet of 300 thousand connected machines becomes something a customer, distributor or service technician can actually act on: dashboards, machine detail, commissioning, service planning, alarms and reporting. The portal has grown over a decade and is now being modernised on two fronts at once. Gen3 platform services, AssetLink and CIAM are landing underneath it, changing the data and the authorization model the screens sit on. At the same time we are mid-way through a design system transition, with a new shared CT UI component library and refreshed UX guidelines rolling into hundreds of existing screens. There is real ground to cover here, e.g. accessibility, perceived performance, a coherent interaction language across the whole portal, and enough freedom to actually fix it. The portal squad is delivering new Gen3-facing features and migrating existing ones in parallel. We are bringing in a senior frontend consultant to add capacity where it is scarcest, the layer the user actually touches, and to help set the frontend patterns the team adopts as the design system transition completes. Where you fit in the organisation: The SMARTLINK program runs under the IoT Manager across four delivery streams: Platform (Gen3), Mobile (iOS/Android/WeChat), Portal + MSM, and CIAM. Each stream has its own Product Owner, analysis, development and testing capacity, with UI/UX, architecture, DevSecOps and support shared across all of them. You join the Solution Design & Development layer of the Portal team, alongside four developers, working to the stream’s Product Owner.You work day to day with the stream’s analysts and with its test engineers, who own portal test coverage — you write and maintain the unit and component tests next to your own code.You work directly with the shared UI/UX team (three designers serving all four streams) from the first sketch onwards, not from a finished handover.You align with the shared architecture group on frontend patterns and with the Platform (Gen3) and CIAM streams on the contracts your screens depend on.Releases run through the shared DevSecOps setup: Azure DevOps pipelines, feature flags, and a 24/7 supported production platform. The role: You own what the user actually touches. Your working level is components, state, interaction and performance: how a screen behaves on a slow connection, what happens while the data is still loading, and whether what we shipped is what was designed and what the user needs. Our frontend is TypeScript and React on Vite and React Router, built on MUI and the shared CT UI component library that Atlas Copco teams use across products. Server state runs through TanStack Query, forms through React Hook Form, real-time updates through SignalR, charts through Highcharts and maps through Azure Maps. We test with Vitest and Testing Library, ship through Azure DevOps pipelines behind feature flags, and instrument the client with OpenTelemetry (New Relic) and Mixpanel so we can see how the portal is really used. Behind the React app sits an ASP.NET Core backend-for-frontend. You are not expected to design domain services, but you are expected to be comfortable there: adding an endpoint, reshaping a response so the UI does not have to compensate for it. What you will deliver: The portal’s user-facing features in React and TypeScript: components that hold up under real data, real permissions and real edge cases, not only the happy path in the mockup.The translation from design to product: working with UX from the first sketch, delivering a usable solution, and saying so when a design does not hold once the data is real.Perceived performance on data-heavy screens: bundle size, render behaviour, caching and loading states on dashboards that pull from a fleet of hundreds of thousands of machines.Contributions back into the shared design system — components, tokens and patterns into the CT UI library instead of building the same thing locally for the third time.Backend-for-frontend extensions where the UI needs them: adding and adjusting ASP.NET Core API endpoints, shaping payloads for the screens that consume them, and keeping the contract honest.Tests next to the product code with Vitest and Testing Library, kept running as a gate in CI/CD.A closed loop with analytics and telemetry: looking at what users actually do and letting that shape the next iteration rather than guessing.AI leverage in your daily work, and a contribution to how the team keeps raising the bar on how it uses AI tooling. Knowledge transfer: This is a consultancy assignment, so what you leave behind matters as much as what you ship. We expect the patterns you introduce to be documented and reviewed with the squad as you go, your components contributed to the shared CT UI library rather than kept local to a feature, and no part of the portal left in a state where only you can maintain it. Profile we are looking for: Essential: You have built and maintained a real web application that other people depend on — not a greenfield demo, but something with history, users and constraints.Several years of hands-on React and TypeScript at senior level: component design, state management, data fetching, and the edge cases in between, owned end to end. You come in productive — there is no ramp-up budget on this assignment.A genuine eye for UX and UI. You care how it looks and how it feels, you can tell the difference between a screen that is finished and one that merely works, you read a Figma file properly, and you notice when spacing, hierarchy or an empty state is wrong.Modern frontend engineering as a habit: a component library and design tokens rather than one-off CSS, and a build and test setup you understand — we work with Vite, Vitest and Testing Library.Accessibility and responsive design as part of how you build, not a checklist at the end.Enough back-end comfort to be useful: consuming and designing REST APIs, and adding or adjusting an endpoint in C# / ASP.NET Core.Strong troubleshooting and root cause analysis. You keep digging until you know why, not just that it failed.Agile / Scrum experience, and the confidence to say in refinement that something should not be built the way it is specified — including to people who do not report to you.Fluency with AI tooling plus the judgement to verify what it produces.Fluent English; on-site in Wilrijk three days per week. Preferred: Experience with agentic AI: building with coding agents, MCP tooling or agent-driven workflows, or bringing AI-assisted interactions into a product UI.Building or maintaining a shared design system or component library used by more than one team.Data-heavy interfaces: charting, maps, dashboards, large tables and real-time updates over SignalR or WebSockets.Product analytics and experimentation: Mixpanel, feature flags, A/B testing, and using the numbers to decide.Working on a localised product across many languages and markets.Affinity with connected physical devices: how a compressor, a sensor or a gateway ends up on a screen.Working inside an identity and permission model — OAuth2/OIDC, roles, multi-tenant customer hierarchies — and reflecting it correctly in the UI.