Senior Software Engineer

Senior Software Engineer Platform / Core Infrastructure London | 4 days a week on site Up to £120k We’re working with a London-based fintech that has scaled rapidly in a short space of time. Their platform now processes billions in annual transaction volume, operating across multiple markets and supporting a fast-growing customer base. This is a Senior Platform Engineer opportunity where you'll take ownership of critical platform initiatives, make key architectural decisions and build the foundations that enable engineering teams to deliver software securely, reliably and at pace. You'll work across cloud infrastructure, Kubernetes, automation and developer tooling, with the autonomy to take projects from initial design through to production. It's an opportunity to make a tangible impact on platform reliability, scalability and the developer experience within a complex, distributed environment. What you'll be doing - Taking ownership of major platform initiatives from discovery and design through to implementation and production. - Designing, building and operating scalable cloud infrastructure across compute, networking, identity and data. - Developing reusable, self-service platform capabilities that help engineering teams deploy and operate services independently. - Driving cloud migrations and workload modernisation, improving consistency, resilience and efficiency. - Building and maintaining infrastructure automation, deployment pipelines and GitOps workflows. - Working closely with engineering and security teams to establish best practices, strengthen platform security and improve observability. - Making pragmatic architectural decisions, balancing reliability, performance, security and operational simplicity. - Mentoring engineers, sharing knowledge and contributing to the ongoing evolution of the platform. - Participating in a compensated on-call rotation and using incident learnings to improve automation and resilience. What we're looking for - Strong experience designing, building and operating production-grade cloud-native platforms. - Hands-on expertise with Kubernetes, Terraform and public cloud environments, ideally GCP or AWS. - Strong software engineering skills in Go, C# or TypeScript, with experience building production tooling, services or automation. - Experience with GitOps, ArgoCD and CI/CD pipelines, including infrastructure automation and policy enforcement. - A solid understanding of distributed systems, networking, IAM and cloud security. - Experience with technologies such as Istio, Cloudflare and modern observability tooling. - A track record of taking technical ownership, making sound architectural decisions and delivering complex initiatives end to end. - A collaborative mindset, with the ability to work across teams, communicate technical trade-offs and understand the needs of developers. Why consider this role? - Real technical ownership: Lead meaningful infrastructure initiatives and influence core architectural decisions. - A platform-first environment: Build reusable capabilities that make life easier for engineering teams. - Complex technical challenges: Work on cloud infrastructure where reliability, security and scalability really matter. - Room to make an impact: Help shape the direction of core infrastructure and raise engineering standards across the business. - If you're a hands-on Platform Engineer who enjoys solving complex infrastructure challenges, building reliable cloud platforms and giving developers the tools to do their best work, we'd love to hear from you. The reality This isn’t a pure DevOps support role. It’s building the platform layer properly - with product thinking, long-term ownership, and a focus on making engineers faster.