Principal Software Engineer, GPS

Principal Software Engineer, Global Public Sector Scale’s rapidly growing Global Public Sector team is focused on using AI to address critical challenges facing the public sector around the world. Our core work consists of: • Creating custom AI applications that will impact millions of citizens • Generating high-quality training data for national LLMs • Upskilling and advisory services to spread the impact of AI We are hiring a Principal Engineer to join a small team of our most senior engineers who take on the problems no one else can. You will work at the earliest stage of our engagements: shaping the technical approach with clients, defining the technology we build on, and turning ideas into working prototypes fast. You will step in when a project is stuck or a problem is unusually hard, and turn what you learn in the field into shared capabilities every team can build on. This is a very senior, hands-on role. Our engineering organisation is young, so mentoring is a core part of the job: you will raise the bar for how we design, build and deliver, and grow the next generation of technical leaders around you. The role is based in London. At Scale, we’re not just building AI solutions, we are building repeatable blocks to enable the public sector to transform their operations and better serve citizens through cutting-edge technology. If you’re ready to shape the future of AI in the public sector and be a member of our rapidly expanding team, we’d love to hear from you. You will: • Take on the hardest technical problems across our programs, stepping in where projects are stuck or the path forward is unclear • Lead the technical side of early engagements: work with clients to scope problems, shape proofs of concept and keep the scope needed to prove value as small as possible • Build working prototypes quickly, from AI agents and evaluation pipelines to data and knowledge systems, and take the most promising ones to production • Define the technology and architecture our solutions are built on, keeping them cohesive, secure and reusable across clients • Mentor engineers across a young organisation through pairing, design and code reviews, and set the bar for engineering excellence • Partner with Directors, VPs and client executives to navigate high-stakes business and technical trade-offs, including travel to client sites as engagements require • Turn patterns from the field into reusable capabilities, contributing components back to our core platform so every engagement starts further ahead • Lead from the front on agentic engineering, both in the AI systems we build and in how our teams use coding agents day to day, and push the boundaries of what’s possible with AI Ideally you’d have: • A strong engineering background, with a Bachelor’s degree in Computer Science, Mathematics or a related quantitative field (or equivalent practical experience) • 10+ years of post-graduation engineering experience, with demonstrated proficiency in languages such as Python, TypeScript/JavaScript, Java, or C++ • 5+ years of experience applying AI/ML in production environments, such as building generative/agentic AI applications, RAG systems or evaluation pipelines • Strong problem-solving skills, with a track record of taking ambiguous, early-stage problems from a blank page to a working prototype and into production • Deep expertise in system design and architecture, including experience with cloud-based machine learning tools and platforms (e.g. AWS, GCP, Azure) • Experience mentoring engineers and raising the technical bar of a team or organisation • Comfort working directly with clients, from their engineering teams to senior executives • Excellent written and verbal communication skills to collaborate effectively in a cross-functional environment Nice to haves: • Past experience in a forward deployed engineering role • Experience working at a startup, particularly as a founding engineer • Experience building a