Principal Software Engineer (Hybrid)

Principal Engineer Location: Waterloo, London, England, UK | Hybrid (1 day per week in office) Who We Are  At 8th Light, we bring life to the best ideas. Founded in 2006 and headquartered in Chicago, we are a technology solutions consultancy that partners with organisations from early-stage startups to the world's largest companies. We take on hard software challenges and turn them into durable results. We build agentic products, the platforms they run on, and the engineering and design at every layer. Our commitment to quality means we deliver solutions we’re truly proud of, while our curiosity sparks innovation and breakthrough thinking. 8th Lights thrive in an environment that champions continuous education, fueling our growth through mentorship and hands-on work. We foster an open, collaborative culture grounded in honesty that builds trust, and believe true success is measured by the outcomes we create for our clients. If this kind of work and our kind of people energises you, you’ve found the right place.  Who You Are You’ve shown long-term repeated success on a variety of projects, typically over the course of 10+ years. You are a trusted expert and leader, often called upon to guide ambiguous initiatives and architect scalable solutions. You bring a blend of deep consulting acumen, technical expertise, and product thinking that drives measurable and impactful outcomes. In your previous experience, you have: Built and shipped production-grade platforms: the reusable foundations, tools, infrastructure, and workflows that help other teams shift faster and more reliably Taken AI and agentic systems from prototype to production, with a strong understanding of infrastructure, authentication, and observability Delivered on  high-stakes consulting engagements across multiple language paradigms, stacks, ecosystems, and client industries  Built high-quality, maintainable software collaboratively, incrementally, and through an approach tailored towards the unique needs of the clients you’ve served  Led the development and delivery of production-grade software using a variety of languages and frameworks, including but not limited to: Java, C#/.NET, Python, TypeScript, JavaScript, React, Go, Ruby, Scala, R, and SQL Actively experimented with AI development tools and translated that experimentation into faster, higher-quality delivery for your teams A track record of understanding, assessing, and embracing new tooling and trends within the software industry Built or integrated AI/ML features into products and systems, including recommendation engines, NLP, computer vision, predictive analytics, RAG pipelines, and agents Successfully led modernisation and replatforming efforts to align legacy systems with short and long-term business needs Led and delivered solutions to architecture-level problems including scalability, security, reliability, performance, maintainability, and observability Facilitated alignment across technic...