Senior Platform Engineer

Senior Platform Engineer LocationLondonEmployment TypeFull timeLocation TypeHybridDepartmentTechnologyInfrastructure EngineeringLemFi (Series B) is building the go-to financial app for the Global South.Moving to a new country shouldn’t mean starting from zero. That's why our team of 400+ spanning 20+ countries is building a financial ecosystem that helps immigrants stay connected to home, build stability, and create wealth regardless of where they are from or where they live.What began as fast, affordable remittances is now evolving into a complete platform for multi-currency accounts, payments, credit, and long-term financial growth.With millions of users across the globe, we process over $1B in monthly transactions to 30+ countries, proving that borders shouldn't limit financial opportunity.About the roleLemFi is the financial engine for people the world wasn't built to serve. We move money, store it, lend it and protect it across ~21 countries - and the platform team is the force multiplier that lets every other engineering team do that at pace. This is the only platform hire we are making this year, which tells you how much we expect from this person.You will design, build and own our internal developer platform: a self-service, AI-powered environment that treats internal engineers as your customers and makes their experience of building on our cloud infrastructure genuinely fast and frictionless. You will touch everything from cloud cost efficiency to developer tooling to the golden paths that let product teams ship without waiting on ops tickets. If you have strong opinions about what great platform engineering looks like and a track record of building things from scratch, not just operating what someone else designed, this is the role.What you'll build and ownDesign and build a self-service internal developer platform, golden paths, templates, guardrails, so engineers can provision, deploy and operate services without raising a ticket.Embed AI-driven automation into the platform: intelligent cost optimisation, anomaly detection, auto-remediation and developer productivity tooling that actually gets used.Own cloud infrastructure on AWS, architecture, cost efficiency, reliability and security posture, with clear metrics and accountability for outcomes, not just uptime.Act as the internal product manager for the platform: talk to engineers regularly, collect requirements, prioritise by impact on developer velocity and run a visible roadmap.Set and enforce platform standards, IaC, CI/CD pipelines, observability, secrets management, turning good practice into the default, not the exception.Identify and fix the biggest sources of friction in the engineering workflow, using data to prioritise and presenting findings to engineering leadership.Work lean and autonomously: this is a high-ownership role on a small team, so you will need to push things to production yourself, not coordinate others to do it.Your experienceProven track record building an internal developer platform or developer experience function from scratch, not just maintaining one someone else built.Deep AWS expertise: you have designed cost-efficient, production-grade cloud architectures and you can defend every line of your Terraform.Strong DevOps and platform engineering fundamentals: Kubernetes, CI/CD, observability stacks, IaC, and the judgement to know when to use each.Experience treating internal engineers as customers, gathering requirements, running a backlog, measuring adoption, not just shipping tools and hoping people use them.Comfortable working without a spec: you have operated in fast-moving environments where you set the direction as much as you follow it.Proficient in at least one scripting or backend language (Python, Go, or equivalent) and confident building automation and tooling, not just configuring managed services.You actively build AI-powered tooling into platform and infrastructure workflows, cost anomaly detection, intelligent...