Senior Full Stack Lead - React/.NET Modernisation Architect

La Fosse; Greater London; Hybrid; GBP 128,000 - 168,000; Part time

Job summary

La Fosse is seeking a Senior Full Stack Developer to modernise a core platform, combining hands-on React development with architectural leadership. The role focuses on creating a new React-driven frontend while integrating with existing .NET backend services and data integrations.

The successful candidate will guide the migration strategy, collaborate with product and business stakeholders, and operate in a hybrid setup with three onsite days in Waterloo, London.

Qualifications

• Significant commercial experience as a Full Stack Developer or Senior Software Engineer.
• Strong front-end experience building React applications from scratch.
• Strong .NET and C# backend development experience.
• Experience leading application modernisation, migration, or transformation initiatives.
• Experience defining software architecture and influencing technical direction.
• Experience building RESTful APIs and scalable enterprise applications.
• Strong stakeholder communication and technical leadership skills.
• Experience working within Agile delivery environments.

Responsibilities

• Lead the migration of the existing Databricks-based application to a modern React‑based solution.
• Define and own the migration strategy, technical roadmap, and implementation approach.
• Assess existing architecture and recommend scalable future-state designs.
• Collaborate with stakeholders to ensure a smooth transition and minimal business disruption.
• Design, develop and maintain modern React applications.
• Build and support backend services using .NET/C# and APIs.
• Drive front-end architecture, coding standards, and component libraries.

Skills

React

.NET/C#

RESTful APIs

Node.js

Java

CI/CD

DevOps

Docker

Kubernetes

Agile

Leadership

Stakeholder comms

Tools

Docker

Kubernetes

Job description

La Fosse is seeking a Senior Full Stack Developer to modernise a core platform, combining hands-on React development with architectural leadership. The role focuses on creating a new React-driven frontend while integrating with existing .NET backend services and data integrations.

The successful candidate will guide the migration strategy, collaborate with product and business stakeholders, and operate in a hybrid setup with three onsite days in Waterloo, London.