React Front End Developer

📍 This is a 3-month contract, fully remote, open to developers in the UK. Satalia says applicants who hear nothing within 2 weeks should treat the application as unsuccessful.

🏢 About Satalia

Satalia is an AI company within WPP that uses AI, optimisation and data science to solve difficult industry problems. It describes itself as a decentralised, flexible-working organisation with a strong focus on wellbeing and inclusion.

🎯 The Role

You will join a small senior team (a technical lead, an architect and QA) building Solve, a shared space in which humans and AI agents work through a problem together on a single board. That board is a live, multi-user canvas, and this contract is hands-on work on it, with the technical lead setting direction and your input shaping how things get built.

🛠️ Tech Stack

• React and TypeScript on the frontend
• Server-Sent Events today, with WebSockets under consideration
• Python and FastAPI on the backend
• Monorepo setup, CI checks, feature toggles and a shared design system

💼 What You'll Do

• Build canvas interactions such as panning, zooming, dragging, selection and card layout, and keep them fast with hundreds of cards on screen
• Organise frontend state across short-lived interactions, saved product data and server-owned data
• Deliver multi-user editing with presence, optimistic changes, reconnection, catch-up after missed events and conflict handling
• Own the browser side of the live event stream, including heartbeats, authenticated streams and backoff reconnects
• Create interfaces for streaming AI responses, agent progress, partial results and approvals
• Set the approach for performance, accessibility and testing in these areas
• Start by finishing the client work that lets several people and agents edit one canvas without losing changes

✅ What You'll Need

• Strong React (or similar) skills and a clear way of thinking about who owns state, how rendering works and what makes the browser slow
• A complex interactive product behind you, for example a whiteboard, mapping tool, design editor or other multi-user app
• Real-world experience with WebSockets or Server-Sent Events, including event ordering and recovery on flaky connections
• Regular, critical use of AI coding agents and interest in the UI problems AI products create
• Confidence working across the API boundary on request shapes, idempotency and who owns which state

🌟 Nice to Have

• Experience with monorepo tooling, CI checks, feature toggles and shared design systems