Senior Full-Stack Developer (.NET + React)
First seen by Alion on Oct 14, 2026.
We are looking for a Senior Full-Stack Developer to join a UK-based digital healthcare company that combines digital tools with clinical expertise to deliver medical and wellbeing services through its online platform.
This role is backend-weighted: you will build ASP.Net Core services that power patient-facing products, and also work on the React frontend that consumes them.
What you'll do
Design and build ASP.Net Core Web APIs and the data layer behind them (Entity Framework Core, SQL Server);
Implement background processing: queues, scheduled jobs, and event-driven messaging;
Build and maintain frontend features in React and TypeScript;
Work with Azure services across the stack: App Service, Storage Queues, Event Grid, SignalR;
Cover your work with tests on both sides: xUnit and Moq on the backend, Vitest or Jest and Playwright on the frontend;
Take part in code review, architectural decisions, and CI/CD improvements.
Requirements
5+ years of commercial development experience;
Strong C# and .NET: ASp.Net Core Web APIs, Entity Framework Core, SQL Server;
Solid experience designing REST APIs;
Practical experience with background processing: queues, scheduled jobs, event-driven messaging;
Strong React and TypeScript: hooks, React Query or similar, component libraries such as MUI;
Hands-on experience with Azure (App Service, Storage Queues, Event Grid, SignalR);
Git, Docker, and CI/CD (GitLab);
Testing: xUnit and Moq, Vitest or Jest, Playwright;
Good spoken and written English.
Nice to have
Node.js and NestJS;
MongoDB, Redis;
Nx monorepo, Redux Toolkit;
Terraform;
Datadog or similar observability tooling.