Principal Software Engineer

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 and deploying large-scale AI solutions
• Experience delivering technology programs for governments or regulated industries
• Experience deploying solutions on-prem or in customer-controlled environments
• Current or previous UK government security clearance (e.g. SC or DV)

PLEASE NOTE: Our policy requires a 90-day waiting period before reconsidering candidates for the same role. This allows us to ensure a fair and thorough evaluation of all applicants.

About Us:

At Scale, our mission is to develop reliable AI systems for the world’s most important decisions. Our products provide the high-quality data and full-stack technologies that power the world’s leading models, and help enterprises and governments build, deploy, and oversee AI applications that deliver real impact. We work closely with industry leaders like Meta, Ernst & Young, Mayo Clinic, Time Inc., the Government of Qatar, and U.S. government agencies including the Army and Air Force. We are expanding our team to accelerate the development of AI applications.

We believe that everyone should be able to bring their whole selves to work, which is why we are proud to be an inclusive and equal opportunity workplace. We are committed to equal employment opportunity regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, citizenship, marital status, disability status, gender identity or Veteran status. 

We are committed to working with and providing reasonable accommodations to applicants with physical and mental disabilities. If you need assistance and/or a reasonable accommodation in the application or recruiting process due to a disability, please contact us at [email protected]. Please see the United States Department of Labor's Know Your Rights poster for additional information.

We comply with the United States Department of Labor's Pay Transparency provision. 

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