Principal Engineer - £135k & Benefits
Location: London / Cardiff (Hybrid - 4 days per month)
About the Company:
Founded in 2014, my client are a B2B fintech on a mission to transform small business lending - a market traditionally underserved despite SMEs representing 99% of all UK businesses.
With nearly a decade of experience powering a digital credit broking marketplace, they’ve evolved into a SaaS provider delivering intelligent, data-driven solutions to banks, lenders, and the broader SME finance ecosystem.
Backed by $10 million in Series A funding and a Series B led by Barclays, their white-label products are used by over 80 leading financial institutions. Now scaled to a 50-person teamm, including 26 engineers, they are hiring a Principal Engineer to help shape the next phase of their growth.
Key Responsibilities:
* Report to the CTO as a senior individual contributor, owning architecture and technical strategy across the platform.
* Design and build scalable, developer-friendly systems—including APIs, data models, integrations, and payment solutions—using Java, Spring Boot, PostgreSQL, Kubernetes, Terraform, and AWS.
* Lead architecture discussions internally and in client-facing settings, guiding trade-offs between speed, flexibility, and scalability, and championing customer-focused, evidence-based decisions.
* Own data engineering responsibilities, including designing and optimising data pipelines to support analytics, decisioning, and platform intelligence.
* Set a high bar for engineering excellence through clear documentation, thoughtful proposals, and strong communication and collaboration practices.
* Work closely with Product Managers and Engineers to explore, validate, and deliver impactful technical solutions.
Your Profile:
* 10+ years’ experience designing and delivering large-scale engineering systems, with at least 2 years in senior technical leadership roles such as Principal Engineer or Architect.
* Strong hands-on expertise across the stack, including Java, Spring, Kotlin, PostgreSQL, MongoDB, AWS, and React.js.
* Proven ability to translate product and business goals into scalable, robust technology solutions while leading agile teams and contributing to strategic roadmaps.
* Comfortable navigating ambiguity and collaborating effectively with both technical and non-technical stakeholders.
* Deep understanding of modern development practices (TDD, CI, CD) and when to apply them to deliver high-quality software.
Nice to Haves
* Experience in Data Engineering or Machine Learning.
* Experience working in SaaS within the fintech sector, with awareness of data management and governance challenges.
* Hands-on experience with Kotlin.
Why join?
Join one of the UK’s most exciting emerging fintechs in B2B lending - with huge backing from Barclays in their Series B and trusted by over 80 leading banks through a proven B2B2C model. With one tier-one client already live and others soon to onboard, this is a rare opportunity to step into a pivotal role and shape the future of SME finance at scale.
You’ll be part of a product-led team at a critical growth stage, supported by strong company benefits, regular team socials, and a collaborative, mission-driven culture.