Principal Software Engineer (London)

Location: Waterloo, London, England, UK | Hybrid (1 day per week in office)

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 technical and non‑technical stakeholders to move initiatives forward through ambiguity and complexity.
• Provided mentorship and team support at scale, while sharing knowledge and improving team practices.
• Collaboratively led stakeholders to balance technical considerations with product and user needs.
• Actively sought out and effectively given feedback.

What You’ll Do At 8th Light

As a go‑to technologist and strategist within 8th Light, you’ll work with a variety of clients, typically one to two in a year, while continuing to deepen your and our collective domain expertise over the course of your career with us. You’ll be responsible for:

• Rapidly building trust with clients, demonstrating technical expertise and understanding of their domain and objectives.
• Driving platform engineering work at the client level, connecting long‑term technical vision to what ships.
• Leading platform strategy and delivery across diverse platform types, connecting long‑term vision to what ships.
• Working pragmatically to balance technology choices while delivering high‑quality work within deadlines.
• Advising clients on architecture, scalability and platform evolution, connecting technical decisions to product and business outcomes.
• Collaborating on systems that involve the full ML lifecycle from data ingestion and preprocessing, to model deployment, integration, and performance monitoring.
• Driving innovation by proactively surfacing new technical approaches and product solutions.
• Leading or initiating formal feedback conversations with teams and clients via retrospectives.
• Clearly articulating and documenting outcomes and driving forward action items.
• Contributing to the health of your team and 8th Light’s culture by modeling our Values.
• Designing and managing high‑level technical roadmaps for large engagements.
• Building your network and maintaining relationships with clients and other industry leaders within your domain.
• Coaching client engineering teams, transferring knowledge and leveling up practices.
• Influencing client CTOs and executive decisions.
• Planning and executing technical work that involves stakeholders outside of project boundaries such as across a client's technical organization.
• Partnering with account teams on planning, opportunity identification, stakeholder relationships, and pre‑sales scope shaping.
• Facilitating retrospectives, strategy sessions, and technical deep‑dives to improve team and project outcomes.
• Identifying, mitigating, and resolving blockers to team progress.
• Contributing to 8th Light by serving as a mentor, leading or designing workshops internally or for clients, representing 8th Light in the tech community, or supporting our hiring processes.
• Demonstrating leadership in scalable system design, modular architecture, and platform‑oriented development.
• Bringing depth in testing strategies, observability, fault tolerance, and secure engineering practices.
• Applying architectural patterns to evaluate tradeoffs and drive clear, documented design rationale.

Strongly Preferred Skills

We work across many areas, and encourage anyone with the experience listed above to apply. We would particularly like to encourage applicants with experience in the following areas:

• Platform engineering: building reusable software foundations, internal developer platforms, and infrastructure that other teams build on.
• Data Engineering: including platforms like Databricks for data processing and analytics.
• Delivering production agentic systems, including RAG pipelines, vector search, and agentic frameworks such as LangChain, LlamaIndex, CrewAI, AutoGen, and n8n.
• DevSecOps.