Lead Platform Engineer (AI Early Stage Startup)

Lead Platform Engineer 📍 Central London (Hybrid, 2–3 days/week) | 💰 Up to £150,000 | 🚀 Just out of seed Own secure, multi-tenant infrastructure end-to-end, from GitOps to compliance controls, in a hands-on, fast-paced role shaping one of the most ambitious applications of AI today. 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. They're a team of 15 across the whole company so 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 clusters Kubernetes on AWS (EKS) across the fleet of production environments Infrastructure-as-code in Terraform/OpenTofu and Terragrunt, the source of truth for everything the company runs Multi-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 to Observability: telemetry, metrics, logging, tracing, dashboards, and alerting that keep a complex distributed system legible Reliability, incident response, and the operational runbooks that protect customer trust CI/CD and release automation that keep the shipping cadence high Developer 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…