Senior Software Engineer - Foundations

LemFi; Greater London; On-site; GBP 90,000 - 140,000; Full time

Job summary

LemFi is seeking a Senior Backend Engineer skilled in Go to join the Foundations tribe, building identity, onboarding, and developer tooling that power our platform. You will own end-to-end systems from design to production, shaping APIs, data contracts, and SDKs while collaborating with platform and infra teams to raise reliability and scalability across services.

You will mentor teammates, participate in reviews, and help define standards that enable product teams to move fast without

Qualifications

• Minimum five years of backend experience with Go as primary language.
• Experience building and scaling distributed systems.
• Experience with platform or enablement teams and internal tooling.
• End-to-end ownership across design to production.
• Experience using AI development tools in daily workflow.
• Strong opinions on system design and API contracts.

Responsibilities

• Own and evolve identity/onboarding services (KYC flows) and data contracts.
• Build and maintain internal SDKs and shared libraries (auth, identity, caching).
• Define architectural standards and API contracts for the wider org.
• Drive engagement platform capabilities (rewards, CRM integrations, LFI cache).
• Partner with platform and infrastructure teams to raise reliability and observability.
• Tackle new country launches, regulatory identity requirements, scaling events.
• Contribute to a high-ownership engineering culture: code reviews, architectural reviews, incident response, mentoring.

Skills

Go

Distributed systems

End-to-end ownership

AI in development

API design

Tools

SDK development

Internal tooling

API gateways

Job description

LemFi (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 role

LemFi's Foundations tribe is the platform backbone every product team relies on. We own onboarding and identity (KYC end-to-end), engagement systems (rewards, CRM tooling, LFI cache), and the internal SDKs and architectural standards that let other squads move fast without reinventing the wheel. If it touches how a customer gets onto the platform or how teams build reliably on top of it, it runs through us.
We are looking for a Senior Backend Engineer who is at home in Go, cares deeply about building things that last, and has the ownership instinct to drive a system from design to production with minimal hand-holding. You will be a key technical voice in the tribe - setting standards, shipping real product, and enabling the rest of engineering to move faster because of the work you do.

What you'll build and own

• Own and evolve our core identity and onboarding services - KYC flows, verification orchestration and the data contracts that downstream systems depend on.
• Build and maintain internal SDKs and shared libraries that abstract platform concerns (auth, identity, caching, eventing) so product teams can move without friction.
• Define and champion cross-platform architectural standards, making opinionated decisions about service design, API contracts and data consistency that the wider engineering org follows.
• Drive engagement platform capabilities - rewards logic, CRM integrations and LFI cache - from spec to production, using AI-assisted development tooling to compress iteration cycles without sacrificing correctness.
• Partner closely with platform and infrastructure teams to raise the reliability and observability bar across Foundations-owned services.
• Tackle the hard, ambiguous problems - new country launches, regulatory identity requirements, scaling events - and turn them into clean, well-documented solutions.
• Contribute to a high-ownership engineering culture: code reviews, architectural reviews, incident response and mentoring are part of the job, not extras.

Your experience

• At least five years of backend engineering experience with Go as your primary language in a production environment.
• A track record of building and scaling distributed systems - you have seen things break at scale and know how to design so they do not.
• Experience working on or closely with platform or enablement teams: shared libraries, internal tooling, developer experience or API gateways.
• Comfortable with the full lifecycle - design, build, operate, improve - with evidence of genuine end-to-end ownership rather than handing off to other teams.
• Practical, demonstrable use of AI development tools in your daily engineering workflow; you validate AI output rather than blindly accepting it.
• Strong opinions about system design, API contracts and service boundaries, backed by real examples you can walk us through.

Nice to have

• Exposure to fintech, payments or identity/KYC systems.
• Experience building SDKs or developer-facing platform services consumed by other engineering teams.
• Prior work in a high-growth startup or scale-up (roughly 50-500 people) where you had to set standards, not just follow them.

Why Join LemFi?

Love shouldn’t be expensive, yet those working hardest for their families often face predatory fees and banking exclusion. We're changing this.

At LemFi, you won’t be just a cog in a machine. Whether designing products, scaling operations, or telling our story, you’ll tackle complex challenges with real, immediate impact. Your work goes beyond metrics - it puts money back in families’ pockets and offers access to the previously excluded. Join us to make a meaningful difference, where high performance is a lifeline for millions.

You can connect with us on LinkedIn and Instagram and if you haven't already, download the app on App Store or Google Play.

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