Senior Software Engineer – Platform & Technical Lead
Permanent
HYBRID
You don't just build features. You own platforms, guide engineering decisions, and make complex systems better.
We're hiring a Senior Software Engineer with a platform mindset and the appetite to take on real technical ownership within a mission-critical, secure software programme.
This is a hands‑on role with genuine weight to it. You will write code, shape implementation approaches, and progressively grow into broader technical leadership, not just execute a backlog.
What you'll be doing
* Owning and evolving significant components within a modular, secure‑by‑design platform.
* Designing and building high-quality software in C# and the modern .NET stack.
* Building and supporting RESTful APIs and distributed services using ASP.NET Core.
* Contributing to frontend implementation in React.
* Designing and optimising relational database solutions with a focus on reliability and performance.
* Supporting cross‑team design discussions and architectural alignment.
* Leading technical investigations, prototypes, and R&D spikes to reduce uncertainty and inform delivery.
* Mentoring engineers within your domain and supporting good engineering practice across the team.
What we're looking for
* 5+ years of professional software development experience.
* Strong C# and .NET background including ASP.NET Core.
* Experience building RESTful APIs, distributed systems, or service‑based architectures.
* React or equivalent modern web framework experience.
* Relational database design and optimisation, ideally PostgreSQL.
* A solid understanding of scalability, reliability, and secure software design.
* Strong analytical and problem‑solving skills.
* The ability to take ownership of complex technical areas and make sound engineering decisions independently.
* Excellent communication and the ability to build trust across engineering teams.
* Docker or Kubernetes experience.
* Messaging or event‑driven architecture patterns.
* Architectural documentation such as C4 diagrams, ADRs, or technical design records.
* Background in defence, government, safety‑critical, or regulated environments.
* Experience with DDD, clean architecture, or modular design patterns.
* Prototyping or R&D spike experience.
Important
You must be a UK national to allow for UK Government security vetting (UKSV) if not already obtained.
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