Avanti are looking for a Software Developer to work with a company based in Swindon. Salary is £35-45k. Company overview Join a growing B2B SaaS company building a commercially successful platform for enterprise customers. We use modern .NET technologies and a React front end, and we prioritise robustness, performance and accessibility. This role is with a small but expanding in-house engineering team where your work will have visible impact. Location & working pattern Hybrid: office-based minimum 3 days per week (commutable to the Swindon area). Full-time, permanent. Role overview We’re looking for an experienced Web Developer to help evolve and modernise our established SaaS platform. You’ll own front-end work, drive a gradual migration from older .NET UI patterns to modern MVC + React, build reusable UI components and collaborate closely with backend engineers, designers and product managers. Key responsibilities * Maintain and enhance an existing .NET WebForms UI while driving an incremental migration to ASP.NET MVC/Razor and React components. * Build and refine React features (components, hooks, routing, forms, error boundaries and user flows). * Consume ASP.NET Core APIs from the front end: data fetching, caching strategies, optimistic updates and resilient error handling. * Create and maintain a reusable component library / design system; manage CSS architecture (SCSS modules or utili...