Principal Engineer - Backend

About us Encord is the universal data layer for AI that helps 300+ AI teams train and run models on the right data. Our platform indexes, curates, annotates, and evaluates data across the full AI lifecycle, from development through production. Trusted by Woven by Toyota, AXA, UiPath, Zipline, and more. We're an ambitious team of 100+ working at the frontier of AI and have raised $60M in Series C funding from Wellington Management, CRV, Next47 and Y Combinator. The role We're looking for a Principal Engineer to join our Foundations team, the backend backbone that builds the reliable, scalable, fast systems everyone else at Encord builds on top of. The team's core challenges sit deep in distributed and data intensive systems. The product mindset on this team is different from most of the company: short-term product insight matters less, long-term matters a lot. Our Foundations team plans around how the next 6, 12, and 24 months will look, with an overarching shape to the problem: handling multiple orders of magnitude the data we handle today. This is our most senior individual contributor role. You'll own the hardest architectural calls, make the trade-offs that shape the platform for years, and raise the engineering bar across the company. Encord is growing rapidly, with our product as the key driver of that growth. A year ago, we were a team of 100, now, we're over 150 and continuing to accelerate. The systems that got us here won't get us to what's next. That's the problem you'll own. What you'll do Design and lead major database and processing-system initiatives Design performant protocols and APIs, such as our label-format API, that customers use directly. This work sits across both product and engineering Build robust distributed systems and reason rigorously about how they fail and how they behave under load Level up engineers across the company through design reviews, pairing, and mentorship, without adding process for its own sake Who we're looking for You've seen and built more than most. You've personally designed, built, and operated large-scale distributed systems in production, and you've lived with your architectural decisions long enough to know which trade-offs actually matter Your impact shows up in the output of the engineers around you, not just your own commits. You make hard things look simple and teach others to do the same You want your work to have a tangible outcome for people. You're not satisfied with building products that do not see the light of day You are a builder. You enjoy all aspects of building not only software but a complete product, and are comfortable moving across the stack when necessary You enjoy problem-solving and thinking from first principles, reach for the simplest solution that works, and know when boring technology wins You're happy to own problems without a predefined, clear definition or obvious solution, and are excited to have autonomy to make decisions as you go You understand that being a member of a high-performing team requires two things. You contribute your best work and help others contribute their best. You'll always lend a helping hand when needed and level up those around you Experience requirements 10+ years building large-scale backend infrastructure applications, including several years operating at staff/principal level with company-wide technical influence Deep expertise in distributed systems (databases, processing systems, replication, partitioning, queuing, caching) and a rigorous understanding of how they fail and behave under load at scale Experience leading large-scale data migrations and system-splitting or re-architecture projects with real customer data on the line Experience owning reliability and operations in production, including monitoring, alerting, and DevOps/SRE A track record of raising engineering quality across teams through architecture reviews, code reviews, testing, rollout, and monitoring practices Demonstrated ability to influence without authority, driving technical alignment across teams in a fast-moving, low-process environment Tech stack We are technology-agnostic at Encord and are not looking for experience across all of these. As long as you're open to learning, please apply. Backend: Python Frontend: TypeScript and React Deployment: Kubernetes Infrastructure: GCP Machine learning: PyTorch, CUDA, Ray Why Encord Competitive salary, commission, and meaningful equity in a high-growth startup Strong in-person culture: the team works from our London office 4+ days/week 25 days annual leave + UK public holidays Annual learning & development budget Travel for customer visits, events, and conferences across the UK and Europe Company lunches twice a week Monthly socials & bi-annual team offsites Find Jobs in United Kingdom on Arbeitnow