Lead Platform Engineer (AI Startup)

Lead Platform Engineer 📍 Central London (Hybrid, 2 - 3 days a week) | 💰 Up to £150,000 The opportunity This is a rare shot to join right at the inflection point. Our client just closed their seed round and is now scaling fast: a team of just 15 building an AI operating system for a demanding, security-conscious industry. A unified intelligence layer that connects evidence, reasoning, and action across a complex, high-stakes lifecycle where getting it right matters enormously. The founding team includes operators who spent years deploying production AI inside some of the world's most demanding enterprise environments. They know what it takes to make ambitious technology hold up under real pressure, and they're now applying that standard to a domain that's ripe for transformation. This is early enough that what you build becomes the foundation everything else stands on, and senior enough that you'll be working alongside people who've done this at the highest level before. The systems being built run inside security-conscious, compliance-bound enterprises, where the infrastructure underneath has to be as trustworthy as the intelligence layered on top of it. The company now needs a Lead Platform Engineer to own that infrastructure end to end. At a company size of 15 (Founders from exceptionally brilliant backgrounds and well known in this field) this isn't a role where you sit in a queue of tickets. You'll be the single, clear owner of how the company deploys, operates, secures, and scales, across its own platform and across isolated customer environments where the bar for trust is absolute. It's a huge amount of responsibility and autonomy, which is exactly the appeal. What you'll own The GitOps deployment backbone on Argo CD, so a small team can ship continuously and safely across many clustersKubernetes on AWS (EKS) across the fleet of production environmentsInfrastructure-as-code in Terraform/OpenTofu and Terragrunt, the source of truth for everything the company runsMulti-tenant, per-customer isolation: standing up a fully isolated, compliant environment for each customer, with its own cluster and data plane, and deploying to it with confidence. This is the hardest and most important part of the job.Security and compliance posture: secrets management, access controls, infrastructure hardening, and the audit-grade controls customers will hold you toObservability: telemetry, metrics, logging, tracing, dashboards, and alerting that keep a complex distributed system legibleReliability, incident response, and the operational runbooks that protect customer trustCI/CD and release automation that keep the shipping cadence highDeveloper experience: making it fast and painless for engineers to deploy and debug Who we're looking for: The ideal candidate will have come from a FAANG, Anthropic, OpenAI, Palantir type organisation, or from an exceptional AI startup, where they have personally owned and built the DevOps function while remaining hands on. This isn't someone who managed a team that did the work. It's someone who did the work themselves at a high standard, and knows what world class infrastructure looks like because they've built it before. At least 5-6 years in DevOps, platform engineering, SRE, or infrastructure and you've operated at a Senior/Lead and above.You've owned production systems rather than only contributing to them, including multi-tenant or customer-specific environments, and you understand the complexity that comes with themDeep fluency with Kubernetes, a major cloud (AWS preferred), GitOps, and infrastructure-as-code, plus the judgment to know when not to add another layerYou come from somewhere that held a high bar, and you expect engineering excellence from yourself and the systems around youYou're hands-on and have no interest in a purely architectural role. You explain complex tradeoffs simply and don't over-engineer.You treat speed, security, cost, and reliability as constraints that all apply at once, and you've struck that balance beforeYou've operated under formal security or compliance regimes (SOC2, HIPAA, or similar) and know how to make controls a strength rather than a tax Why this role: Ground floor of something huge: 15 people, large seed funding, and a mandate to build the infrastructure backbone from the ground upReal ownership: you're not one of many DevOps hires. You're the DevOps hireCentral London, hybrid 2–3 days a week: flexibility without losing the energy of an in-person team. For the right person they will consider more flexible arrangementUp to £150,000, reflecting the seniority and trust this role carries This is a high-intensity, high-stakes role. The team moves quickly and gives direct feedback, the responsibility you carry will likely outrun your title, and you'll go wherever the work needs you most, which sometimes means unglamorous tasks that matter more than anything else that week. The people who thrive here find that kind of ownership and growth exciting, and they weren't looking for a nine-to-five.