What is Flagstone?
Flagstone is many things. An online savings platform, reinventing how individuals, businesses, and charities manage, protect, and grow their cash. A diverse group of people, bound by a collaborative spirit, and shared purpose. And lastly, a thriving, profitable business – where smart people do their best work.
Each definition shares a common thread: our unique culture. It’s our pride and joy. And our competitive advantage.
A feel for our culture:
To revolutionise the savings market, we need to be at our best. But high performance takes more than talent – it takes a culture of kindness, respect, and growth.
That’s why we’re building a diverse, inclusive community, where your voice is heard and valued. Where, with close support and room to develop, you can surpass even your own expectations. And be rewarded for it.
We may not change the world, but we can change the world of financial technology. And all it takes is a winning mix of drive, talent, and empathy. Our culture celebrates all three.
But enough about us. Let’s talk about you.
Does this sound like you?
You're a hands-on Engineering Lead, ideally with around 10 years' experience, ready to run a squad with real autonomy. You'll lead the Banks squad on the Bank Portal, the partner-facing application our banking partners use to view and act on their Flagstone relationship. By the time you start, the squad will have delivered the foundational rebuild (migrating banks off the legacy tool to full feature parity), and you'll pick up the next phase: building the commercial capability on top of that foundation and turning the portal into a genuine commercial engine for the partnership.
This is a full-stack squad (.NET backend, React/TypeScript frontend) working in a regulated, data-sensitive environment, so the role carries real weight: partner-facing delivery, strict data isolation between banks, and the judgement calls that come with both.
What you’ll do:
You'll own the squad's technical direction and quarterly roadmap, not just participate in it, driving the commercial features that build on the migrated foundation (self-serve rate changes, new product submissions, liquidity data) while keeping the newly-migrated platform stable and any remaining cohorts or legacy decommissioning on track. You'll make most technical debt and risk calls autonomously, escalating only where tribe-level coordination is genuinely needed.
On people, you'll run day-to-day delivery and performance management, including the harder conversations, handling underperformance and any exits directly rather than deferring them upward. Within the FTC's 12 months, expect the emphasis to sit more on driving commercial delivery at pace than on longer-term development pathways, though coaching engineers and creating stretch opportunities is still part of the job.
You'll also work as a peer across the tribe: contributing to engineering-wide standards, comparing notes with other Team Leads, and representing the squad's constraints and progress in tribe-level planning.
What you’ll bring:
We're a Microsoft shop: C#/.NET is our core backend language, on Azure, cloud-first. The Bank Portal specifically runs on .NET (Aspire, Duende BFF, YARP) with a React/TypeScript frontend, so while backend depth is the priority, comfort reviewing across a full-stack architecture matters more here than on a purely backend squad.
We'd like to see a good mix of:
Strong commercial C#/.NET experience, with a solid grasp of SOLID, event-driven architecture and DDD
RESTful API design and SQL skills
Cloud-native Azure development
Enough frontend fluency to review React/TypeScript work, even if you're not hands-on day to day
TDD in practice (NUnit, MSTest, Playwright/Selenium or similar)
Experience with agentic development tools (Claude Code or similar)
Comfort working in a regulated or data-sensitive environment, this squad enforces strict per-bank data isolation and audit logging as a core part of the architecture
Comfort working in an agile environment, and being the final escalation point for decision making
An ability to assess and weigh risk, making sound, defensible decisions rather than deferring by default
And on the people side:
A track record of direct, fair performance management, including the difficult conversations
Confident stakeholder management, and the ability to translate technical trade-offs for non-technical audiences
Genuine enthusiasm for coaching and developing engineers
Proactive, collaborative problem-solving
How we reward you:
At Flagstone, the benefits extend beyond false gifts like “fruit and snacks”. Instead, we invest in your health, wealth, and professional development. Here’s a selection of our benefits:
Hybrid working - Pop into our London office to spend time with team
Competitive bonus scheme - designed to reward and recognise high performance
Flexible benefits budget - a pot to fund meaningful benefits for you, whether it's hormone or fertility testing, cancer screening, neuro-diversity coaching or something that matters for you.
A range of salary sacrifice options to help you make tax efficient savings on electric cars, nursery schemes, home and tech goods.
Around the World scheme - 3 months work from anywhere scheme (some exclusions do apply)
Mental wellbeing support – Access therapy and mental health sessions through Spill
Learning and development – £1,000 personal development budget to help you grow in your role.
Private health care - Enjoy all the benefits AXA has to offer, including reduced gym memberships and medical history disregarded
Medical cash plan - To help you with the costs of dental and optical expenses
Life insurance and Income Protection- four times your annual salary for peace of mind
Matched pension contributions up to 5%
25 days holiday - plus bank holidays, well-being days and volunteering days
Enhanced Parental Leave – enhanced maternity, paternity and adoption pay.
All are welcome.
At Flagstone, we’re assembling a diverse team that defies our industry’s norms. Think this role could suit you? We encourage you to apply, no matter your background.
Find Jobs in United Kingdom on Arbeitnow