Lead Software Engineer (Python)

Description

Our client is an industry leader when it comes to AI. Their mission is to redefine how humans and machines work together; building AI that is safe, reliable and genuinely useful. You'll be at the heart of it: designing, prototyping and delivering LLM-powered applications and agentic workflows that solve real-world client challenges.

• Solve complex problems across a wide variety of client environments.
• Lead technical discussions and support less experienced engineers.
• Implement testing and evaluation frameworks covering prompt quality, agent behaviour, and output reliability.
• Apply modern AI technologies where appropriate, such as RAG/GraphRAG, knowledge graphs, vector databases and data pipelines.
• Architect scalable, cost-effective solutions that balance innovation with constraints such as compliance, performance and security.
• The Lead Engineer will build and extend platform capabilities using Python, including APIs, integrations and backend services.

Requirements

MCS Group are seeking a Lead Software Engineer with deep commercial experience in Python for an exciting new role in a scaling technology company. A perfect opportunity for a senior Python engineer who wants to build real, high-impact AI systems and have true autonomy in an exciting organisation.You'll join a growing team developing next-generation AI solutions for some of the most complex and secure environments in the world across a range of diverse sectors.

• You'll have strong experience as a software engineer, ideally building production-grade applications and products in Python
• Comfortable working within agile engineering teams.
• You'll have an interest in AI and an awareness of LLM APIs, including function calling, prompt engineering and evaluation.
• Proven backend/API development experience with FastAPI or similar.

Benefits

• Up to £85,000 with a leading benefits package which includes amazing annual leave entitlement (one of the best in the private sector) and share options.

Training + Development

Interview process

Visa Sponsorship

Security clearance