Lead Software Engineer

Our client, an innovative UK technology company is building a next-generation AI platform for defence and health applications
. Their systems operate in highly regulated, mission-critical environments where reliability, security, and performance truly matter.

We’re looking for a Lead Software Engineer to take technical ownership of key platform components, guide architectural decisions, and mentor engineers as we scale. This is a hands-on leadership role — you’ll be writing code, shaping systems, and directly influencing the future of the platform.

This is a genuine ground-floor opportunity to shape both the technology and the engineering culture within a growing, mission-driven business.

• Leading the design, development, and evolution of intelligent, distributed systems
• Architecting and building AI-driven capabilities
  , including:
• Retrieval-Augmented Generation (RAG)
• AI agents and orchestration workflows
• Designing and maintaining backend services and APIs (primarily Python, FastAPI / Flask)
• Building and scaling data pipelines and search systems using:
• Elastic Search, Weaviate, Pinecone, and other vector databases
• Engineering secure, containerised architectures using Docker and Kubernetes
• Ensuring high availability, fault tolerance, and performance for mission-critical workloads
• Providing technical leadership and mentorship to other engineers
• Contributing to technical strategy, tooling choices, and engineering best practices

• Active SC clearance and British nationality (no dual nationality)
• Degree in Computer Science, AI, or a related field — or equivalent industry experience
• Strong background in Python or similar languages
• Significant experience with backend development
  , microservices, and distributed systems
• Hands-on experience with AI/ML systems
  , including LLMs, RAG, or vector databases
• Solid understanding of containerisation and orchestration (Docker / Kubernetes)
• Experience delivering secure, on-premise or regulated systems
• Proven ability to lead technically
  , mentor others, and take ownership of complex problems
• Experience in defence, government, healthcare, or other regulated domains
• Familiarity with Dev Ops practices, CI/CD pipelines, and infrastructure as code
• Exposure to data engineering, ETL pipelines, or high-volume data processing
• Experience working in SME or start-up environments
  , comfortable wearing multiple hats

Hybrid working – 1 day per week onsite in either Winchester/Basingstoke