Senior.NET Engineer | £85K | Hybrid 3 days in London | Fintech Client

A leading FinTech business based in Central London is looking to hire multiple Senior.NET Engineers to join a major transformation programme focused on modernising one of its core technology platforms.

You will join as one of the first senior engineers in a growing development team, helping to shape the technical direction of a new platform from an early stage. The role will involve modernising and migrating an existing system onto a new greenfield solution, with plenty of opportunity to influence architecture, engineering standards and development practices.

This is a hands-on senior engineering position, with a core technology stack including C#,.NET, Azure and Event-Driven Architecture.

Salary & Location:

• Salary up to £85,000 + bonus + benefits
• Based in Central London
• Hybrid working with 3 days per week in the office

Key Responsibilities:

• Design and develop high-performance backend and integration services using C# and.NET, supporting systems processing very large volumes of data at terabyte scale.
• Build scalable, resilient and highly performant applications capable of operating within demanding, data-intensive environments.
• Develop and maintain APIs, event-driven services and distributed applications connecting internal platforms and services across the wider technology estate.
• Work with event-driven and messaging architectures to process and distribute high volumes of data efficiently and reliably.
• Design solutions with a strong focus on performance, throughput and latency, making appropriate architectural and engineering trade-offs for performance-sensitive systems.
• Develop applications within a distributed private-cloud environment, where infrastructure is hosted across geographically distributed, internally managed machines rather than a traditional public-cloud model.
• Build and deploy containerised services, working within an environment where lightweight container orchestration and performance are prioritised over traditional Kubernetes-based deployments.
• Apply strong software engineering principles around multithreading, concurrency, scalability, resilience and distributed systems where appropriate.
• Follow established practices around automated testing, CI/CD, Git-based development and observability to deliver reliable production software.
• Collaborate closely with Architects and Engineers to help define the architecture and technical direction of the new platform.
• Produce and maintain clear technical, service and process documentation.
• Mentor and support other engineers, promoting strong development practices across .NET, distributed systems and event-driven architecture.
• Ensure solutions meet required security, governance, compliance and supportability standards.