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Be ready to discuss API design, data modeling, concurrency, observability, and trade-offs you’ve made on production back ends. Expect coding plus system-design depth for a senior bar.
Strong fit if you already lead back-end delivery, thrive in an in-office London team, and can own services end to end at senior scope for Flagstone.
As a Senior Back End Engineer at Flagstone in London, expect to design and ship server-side services, own APIs and data flows, review designs with peers, and harden production systems for reliability and security in a fixed-office setting.
No—the listing is for Flagstone’s London office (Great Castle Street / Mayfair area), not remote.
Independent ownership of back-end systems, sound design judgment, and mentoring or elevating team engineering practice.
freeCodeCamp, Saylor CS courses, CS50, and Microsoft Learn developer paths (costs: free / free to learn as listed).
Senior Back End Engineer - ContractFlagstoneLondon Office Role Overview We are seeking a Senior Back End Engineer to join our dynamic team at Flagstone. As an experienced professional, you will be responsible for delivering high-quality systems and maintaining robust architecture in a cloud-based environment. You will collaborate with cross-functional teams to identify technological solutions that address business challenges. Core Duties Develop and maintain scalable, efficient back-end systems using C# on the Microsoft stack. Design and implement system architecture for large-scale projects in a cloud environment (Azure). Work closely with relevant teams to understand business needs and translate them into technical solutions. Ensure high-quality code standards are met through rigorous testing and continuous integration practices. What We're Looking For 7+ years of experience in back-end development, preferably with a focus on C# and cloud technologies like Azure. A deep understanding of system design principles and the ability to architect complex solutions. The capability to explain "how and why" technology is designed and delivered within an organization. Strong communication skills for effective collaboration across teams. About Flagstone Flagstone is a forward-thinking online savings platform dedicated to transforming the way individuals, businesses, and charities manage their cash. Our success stems from our diverse team, united by a collaborative spirit, shared purpose, and a commitment to kindness, respect, and growth. We offer a supportive environment where you can thrive and exceed your expectations. Applying for This Role To apply, complete your application directly on this page, or you'll be redirected to the employer's application platform to finish submitting there. Let’s revolutionize financial technology together! To apply, complete your application directly on this page, or you'll be redirected to the employer's application platform to finish submitting there.
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