Lead Software Engineer - Belfast

Requirements

Must have:

- Strong experience as a software engineer, ideally building production-grade applications and products in Python - Interest in AI and awareness of LLM APIs, including function calling, prompt engineering, and evaluation - Proven backend/API development experience with FastAPI or similar - Comfortable working within agile engineering teams

Responsibilities:

- Build and extend platform capabilities using Python, including APIs, integrations, and backend services - Implement testing and evaluation frameworks covering prompt quality, agent behavior, 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 - Lead technical discussions and support less experienced engineers - Solve complex problems across a wide variety of client environments - Contribute to a culture of learning, coaching, and technical excellence

Company:

We are MCS Group, seeking a Lead Software Engineer with deep commercial experience in Python for an exciting new role in our scaling technology company. This is a perfect opportunity for a senior Python engineer who wants to build real, high-impact AI systems and have true autonomy in our organization. Youll join a growing team developing next-generation AI solutions for some of the most complex and secure environments across diverse sectors. Our mission is to redefine how humans and machines work together; building AI that is safe, reliable, and genuinely useful. With a salary of up to £85,000 and a leading benefits package, including an exceptional annual leave entitlement and share options, we are committed to fostering a dynamic and supportive work environment.