Senior Full Stack Developer (.NET Core + React)

About the Role:

We are looking for a passionate Senior Full Stack Developer with strong expertise in ASP.NET Core and React for a full-time, work-from-home engagement. You will be placed with a European-based client and work directly alongside their in-house developer on feature development, maintenance, and bug fixing of a multi-tenant SaaS application aligned to European working hours. This is a 12-month contractual engagement, with a 2-month probation period and a 2-month notice period on either side. If you take pride in writing clean, maintainable code and thrive in a remote, cross-border collaborative environment, we want to hear from you!

The Highlights: Why This Role Stands Out

• Remote-First Engagement: This is a fully work-from-home role, operating on European working hours (Monday to Friday, 40 hours per week) in support of a Europe-based client.

• Collaborative Development: You will work hand-in-hand with the client's in-house developer, who owns the overall architecture and technical direction, contributing actively to day-to-day development and maintenance.

• Full-Stack Ownership: Work across a modern stack ASP.NET Core 8 backend, React 19 frontend, and PostgreSQL delivering end-to-end features.

• Modern Frontend Ecosystem: Build responsive, accessible UIs using React 19, TypeScript, MUI, Formik, and Chart.js within a Vite-powered development environment.

• Cloud-Deployed Application: Work on an application hosted on AWS (acceptance and production), with deployments managed through AWS CodeDeploy and Docker on EC2.

• Growth Path: Initial focus on feature development and bug fixing, with potential involvement in architecture and scalability improvements based on performance.

Key Responsibilities:

• Develop, maintain, and enhance features across the full stack (ASP.NET Core backend + React frontend).

• Build and integrate responsive UI components using React 19, TypeScript, MUI, and Formik/Yup.

• Write and maintain backend APIs using ASP.NET Core and .NET 8, with PostgreSQL via Entity Framework Core 8.

• Participate in code reviews, maintain code quality standards, and contribute to technical documentation.

• Identify, diagnose, and resolve bugs across the application stack.
• Collaborate closely with the lead developer on sprint planning, feature scoping, and technical decisions.

• Support basic CI/CD workflows using GitHub and AWS CodeDeploy.
• Write unit and integration tests using Vitest and Testing Library on the frontend.

Required Backend Skills (Must Haves):

• ASP.NET Core & .NET 8: Solid hands-on experience building RESTful APIs and backend services.

• PostgreSQL: Strong working knowledge of PostgreSQL for relational data modelling, querying, and optimisation.

• Entity Framework Core 8: Proficiency in EF Core for ORM, migrations, and query optimisation. Comfort with upcoming upgrade to EF Core 10.

• Multi-Tenancy Concepts: Understanding of multi-tenant application architecture (experience with Finbuckle MultiTenant is a plus)

• Authentication & Security: Familiarity with AWS Cognito, Amplify, and JWT-based authentication flows.

Required Frontend Skills (Must Haves):

• React 19 & TypeScript: Strong experience building scalable, component-driven UIs with React and TypeScript.

• MUI & Emotion: Hands-on experience with Material UI and CSS-in-JS for responsive, accessible design.

• Forms & Validation: Proficiency with Formik and Yup for complex form management.

• Routing & HTTP: Experience with React Router and Axios for client-side navigation and API integration.

• Testing: Working knowledge of Vitest and Testing Library for unit and component testing.

• Internationalisation: Familiarity with i18next for multi-language support.

• Data Visualisation: Experience with Chart.js for rendering charts and dashboards.

Good-to-Have Skills:

• Experience with Hangfire for background job scheduling.

• Familiarity with Docker for containerised development environments.

• Exposure to AWS services — EC2, CodeDeploy, Cognito.

• Experience with Vite as a frontend build tool.

• Understanding of CI/CD pipelines and GitHub-based workflows.

• Knowledge of Microsoft Identity Web for identity management.

Infrastructure & Ways of Working:

• Source Control: GitHub for all source code management.

• Deployment: AWS CodeDeploy for automated deployments to acceptance and production environments on AWS EC2.

• Containers: Application runs in Docker containers on EC2 (local dev is non-containerised).

• CI/CD: Basic CI/CD pipeline in place; comfort with standard deployment workflows expected.

• Development: Local development environment; acceptance and production environments hosted on AWS.

What We Offer:

• Fully remote, work-from-home engagement — no commute, no relocation.

• 12-month full-time contract with a structured 2-month probation period.

• Exposure to a European client environment and international ways of working.

• Opportunity to work on a live, growing multi-tenant SaaS product.

• Close collaboration with an experienced lead developer — learn while you contribute.

• Clear path to expanded responsibility in architecture and scalability as you grow in the role.