Sr. Full Stack Developer

We are seeking an experienced Tech Lead to spearhead the modernisation of a large-scale enterprise application from legacy ASP.NET to a modern .NET 10 Web API and React stack. You will own the technical direction of a cross-functional delivery pod, mentor a team of developers, and drive hands-on engineering across both frontend and backend.

This is a hands-on leadership role - you will write production code, lead architecture decisions, and be accountable for the technical quality of everything your pod delivers. You will work in a structured Agile environment, collaborating closely with the Solution Architect, QA leads, and client stakeholders across a multi-year, multi-phase modernisation programme.

What You Will Do

Technical Leadership

• Own end-to-end technical delivery of your pod - architecture, design, coding, code review, and quality gates

• Lead the migration from legacy ASP.NET (MVC / Web API / Web Forms) to .NET 10 REST APIs and React 18 frontend

• Define and enforce coding standards, branching strategy, and PR review process across the pod

• Produce Architecture Decision Records (ADRs) for all significant technical choices

• Conduct structured code reviews covering architecture, security, performance, and maintainability - not just syntax

• Identify and resolve technical debt proactively; maintain a tech debt register visible to stakeholders

• Set up and maintain CI/CD pipelines (GitHub Actions / Azure DevOps) with quality gates: SonarQube, unit coverage, OWASP dependency scan

• Collaborate with Solution Architect on cross-pod API contracts, shared services, and infrastructure decisions

Hands-On Engineering

• Design and build .NET 10 Web API microservices using Clean Architecture and Domain-Driven Design patterns

• Build React 18 SPAs: component architecture, Redux Toolkit / Zustand state management, routing, and performance optimisation

• Implement OAuth2 / OIDC / JWT authentication and role-based access control

• Design and optimise relational database schemas (SQL Server / PostgreSQL); write complex LINQ and EF Core queries

• Build and consume RESTful APIs with versioning, error handling, and OpenAPI documentation

• Write unit, integration, and contract tests as a core part of the Definition of Done

Migration & Modernisation

• Lead the technical approach for migrating legacy ASP.NET code to .NET 10 - analysis, characterisation testing, phased migration, parity validation

• Use GitHub Copilot and AI-assisted tooling to accelerate migration while maintaining review discipline

• Identify breaking changes, deprecated dependencies, and third-party package migration paths

• Establish repeatable migration patterns that the whole pod can follow consistently across modules

• Ensure all migrated code has adequate unit test coverage before merge - parity tests are non-negotiable

Team Leadership & Mentoring

• Lead a pod of 4-6 engineers (mix of senior, mid, and junior developers)

• Run daily technical standups, remove technical blockers, and escalate risks to the Architect early

• Mentor mid and junior developers through pair programming, code reviews, and 1:1 technical guidance

• Create a learning environment - internal tech talks, documentation, actionable review feedback

• Make resourcing recommendations and flag capacity risks to the Delivery Manager

Agile Delivery (Added Advantage)

• Participate in Scrum ceremonies - Sprint Planning, Daily Standup, Sprint Review, Retrospective, Backlog Grooming

• Collaborate with the Product Owner / BA to refine user stories, provide technical input on acceptance criteria, and raise technical stories

• Provide accurate SP estimates; track sprint progress and flag scope risk early

• Support the Scrum Master in removing impediments with a technical root cause

• Champion the Definition of Done - ensure every story that ships meets quality, test, and documentation standards