Senior Platform Engineer

About Saturn

Saturn is a Series A, Y Combinator-backed startup building the AI‑native operating system for the £100B+ financial advice industry. We believe advice will always be human, and we build technology that makes human advisers extraordinary. Advisers currently lose up to 70% of their time to administration and compliance. Saturn automates this, giving advisers back their most precious resource so they can focus on what they do best: serving clients. We are compliant by design, trusted by 500+ firms and 3,000+ advisers across the UK. Our engineers are early and founding team members from Rippling, Cred, Postman, Gojek, and Slice. We are a small team that orbits together, moves with purpose, and holds a high bar.

About The Role

As a Senior Platform Engineer at Saturn, you own the backend architecture and infrastructure that the entire product runs on. You make architectural decisions that affect every service, set the technical standard for reliability and correctness, and build the foundation for Saturn's next phase of scale. You are a backend engineer with deep fundamentals who builds the systems that everything else depends on. You design and own core financial services infrastructure: data pipelines, integrations with back‑office and adviser platforms, and the reliable, secure services that underpin Saturn's compliance and workflow engine. You think in systems, obsess over correctness and reliability, and are energised by the challenge of building infrastructure that has to be right every time. At the senior level, you drive architectural decisions, mentor other engineers on backend best practices, and ensure Saturn's platform can scale to support a custody product and international expansion.

What You Will Do

• Design, build, and maintain scalable backend infrastructure in Go and TypeScript.
• Make architectural decisions that serve the platform for years.
• Own reliability, performance, and observability of Saturn's core services: data ingestion pipelines, AI/LLM infrastructure, compliance automation engines, and user‑facing APIs.
• Build highly reliable, fault‑tolerant services that handle sensitive financial data with the correctness and auditability that a regulated environment demands.
• Manage and scale Saturn's AI infrastructure: LLM API integrations, ML pipelines, prompt management systems, and the proprietary compliance rule engine from our ATEB acquisition.
• Integrate with third‑party financial platforms, back‑office systems, and data providers, building robust, well‑tested connectors that form Saturn's system of record.
• Drive architectural decisions as Saturn scales across the UK market and prepares for custody platform requirements: data integrity, audit trails, compliance infrastructure, and security.
• Own the quality of your work. Write well‑tested code. There is no QA team. You are responsible for what you ship.
• Mentor other engineers on backend architecture, system design, and operational best practices.
• Maintain strong documentation and champion operational excellence across the engineering culture.

What You Will Need

• 5+ years of experience building backend systems in production, ideally in fintech, payments, or other data‑critical environments.
• Strong hands‑on experience with Go and TypeScript.
• Architectural judgment: you design systems that are correct, reliable, and maintainable. You think about how changes ripple across a complex, integrated platform.
• Deep understanding of cloud infrastructure (AWS preferred) and how to deploy and operate backend services reliably at scale.
• Experience designing systems that handle sensitive financial or regulated data, with a strong appreciation for data integrity, auditability, and correctness.
• Strong grasp of distributed systems, event‑driven architecture, and building fault‑tolerant services.
• Experience mentoring engineers and setting technical standards through code review and architectural guidance.
• Experience building integrations with third‑party APIs, financial platforms, or back‑office systems.
• Clear communicator who writes well, asks sharp questions, and collaborates effectively across disciplines.
• Self‑directed: you identify infrastructure risks, propose solutions, and drive them to completion.
• Prior fintech, regtech, or regulated industry experience is a strong plus.

Our Values

We care deeply about the culture we build. We hire people who are obsessed with doing great work, who seek truth over comfort, who earn trust rather than assume it, and who succeed and fail as one team.

What We Offer

• Competitive salary benchmarked to your experience and the London market.
• Equity / stock options, a genuine stake in Saturn's success.
• On‑site in our London office.
• Work on genuinely hard infrastructure challenges at the intersection of fintech, regulation, and AI.
• High ownership and autonomy, you are building the foundation of a company with a path to 50x revenue growth.
• A tight‑knit, ambitious team that cares deeply about engineering quality and each other.