Client: Incubated fintech startup
Location: London, UK (Hybrid)
The Context
A major enterprise payments division is being carved out from a top-tier global banking group to establish an independent, modern technology business. Rather than maintaining legacy banking infrastructure or owning a tiny slice of a massive corporate estate, this project offers the rare chance to build a high-scale tech company from the ground up.
The engineering organisation is scaling rapidly from the foundation up, with the product-facing engineering org ultimately expanding to 100–200 engineers across ~12 teams, alongside a dedicated platform and infrastructure group of 20–30 engineers. With a explicit bias towards hiring experienced engineers in the first 3–6 months, early joiners will have an outsized influence on technical architecture, tooling, coding standards, and engineering culture.
The Role
As a Senior Software Engineer, you will be on the front lines of building core product capabilities and infrastructure from scratch. You will take ownership of complex technical problems, architect production-grade services, and help set the bar for code quality, testing, and system reliability across the business.
This is a high-autonomy, greenfield environment ideal for engineers who enjoy navigating ambiguity, designing distributed systems, and building rather than maintaining legacy systems.
What You’ll Be Doing
- Greenfield Delivery: Write clean, production-ready, testable code to build resilient, high-throughput payment systems from 0 to 1.
- System Design & Architecture: Drive technical design for new domain services, focusing on scalability, security, and low latency.
- Technical Standards: Establish best practices for testing, continuous integration/deployment (CI/CD), observability, and code reviews.
- Product & Domain Collaboration: Work closely with Product Managers and Engineering Leads to break down complex business problems into clear technical roadmaps.
- Cultural Influence: Help shape how teams ship software, evaluate new technologies, and make build-vs-buy decisions early in the organisation's lifecycle.
- Mentorship: Elevate the technical bar of the engineering team through peer code reviews, pair programming, and architectural guidance.
Core Stack:
- Frontend: TypeScript
- Platform / Tooling: Golang, Python
Tech Philosophy: You do not need deep, day‑one expertise in every single language in the stack. What matters most is strong computer science fundamentals, system design capabilities, and a pragmatic "right tool for the job" mindset. The hiring process (including a take-home technical exercise) evaluates engineering judgment, code quality, and problem‑solving over syntax memorization.
What We’re Looking For
- Proven Track Record: Solid experience as a Senior Software Engineer working on production-grade, high-scale software systems (preferably in fintech, payments, or cloud-native digital products).
- Core Engineering Strength: Strong fluency in strongly typed languages (e.g., Kotlin, Java, Rust, Go, C++) with an eagerness to work with Rust and Kotlin in production.
- Distributed Systems Fundamentals: Experience with event-driven architectures, API design, data consistency, high availability, and cloud-native infrastructure.
- 0-to-1 Mindset: Ability to thrive in an environment where foundations are still being laid—bringing structure without adding unnecessary friction.
- Quality Orientation: A strong belief in automated testing, CI/CD automation, and operational ownership.
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Senior Software Engineer (kotlin/Rust) employer: numi
Join a world-leading sports brand that is revolutionising the way millions engage with their favourite physical sport through innovative software solutions. With a remote-first approach and the flexibility of hybrid working, you will thrive in a dynamic environment that fosters collaboration and personal growth, while directly learning from industry experts. This is an exceptional opportunity to contribute to a product that users love, all while enjoying a supportive culture that values your input and encourages continuous development.
