Principal Software Engineer; platform

Retained Search:
Principal Software Engineer (Platform) | London (Hybrid)

I’m thrilled to announce that Numi has been retained to find a Principal Platform Engineer for one of the most exciting Fin Tech carve‑outs in the UK right now.

Backed by a massive, multi‑hundred‑million‑pound strategic investment from a global private‑equity powerhouse, this newly formed entity processes billions of pounds annually, providing critical payments infrastructure to the UK economy. They are currently building a standalone tech organisation from the ground up, meaning a greenfield opportunity backed by enterprise scale.

Our client’s Platform & Infrastructure team provides the hardened, high‑velocity foundations that allow product teams to ship code confidently. We need a Principal Engineer who is both an architect of engineering principles and a hands‑on build engineer.

• Owning Developer Experience (DX): Designing, operating, and refining an Internal Developer Platform (IDP) that scales with a rapidly growing set of product teams.
• Distributed Systems: Leading the migration toward and optimisation of highly available, low‑latency systems.
• Frictionless Compliance: Creatively integrating controls and compliance into the SDLC so they empower engineers to ship multiple times a day, rather than acting as blockers.
• Observability: Building the tooling (monitoring, logging, incident response) that allows teams to see around corners.
• Mentorship & Leadership: Leveling up the engineering org through RFCs, workshops, and fostering communities of practice.

• Battle‑Tested
  
  Experience:
  
  You’ve built complex, scalable systems, seen things break at scale, and know exactly how to prevent them.
• Cloud & Infra Mastery: Deep command of cloud infrastructure, Kubernetes, and the broader CNCF ecosystem.
• Polyglot Mindset: Expertise in at least two modern languages (e.g., Rust, Go, Kotlin) and a strict “right tool for the job” philosophy.
• Product Thinking: You treat the platform as a product, viewing your fellow engineers as your primary customers.
• Exceptional Communication: You can translate complex technical trade‑offs to non‑technical stakeholders effortlessly.

• Strong opinions, weakly held: Objective, pragmatic decision‑making.
• Automate everything: Everything‑as‑code. If you do it three times, it’s a feature for the back‑end.
• Logging simplicity is a feature: Boring, reliable tech > flavour of the week.
• Absolute Ownership: You build it, you run it, you fix it.

London (Hybrid – 3 days a week in a brand‑new office space).