Principal/ Senior Software Engineering
Location: London Working: Remote Salary: £100K - £120K
About the Company
We’re working with an innovative, fast-growing FinTech that is transforming the mortgage industry through technology and AI.
The business is on a mission to make borrowing more accessible while helping mortgage brokers navigate complex affordability and risk challenges through smarter technology.
Following significant growth, the company increased its annual lending volumes by over 80% to approximately £350m in 2025 and is continuing to invest heavily in its technology and AI capabilities.
The Role
We’re looking for a hands-on Technical Lead to help shape and build the next generation of a modern lending platform.
This is not a traditional management position. You’ll remain deeply involved in designing, building, testing and reviewing production software, while also helping shape the architecture, technical roadmap and engineering standards.
AI is at the heart of the role. You’ll work hands-on with LLMs, RAG, agentic workflows and AI-enabled services, taking ideas from rapid experimentation through to secure, reliable production systems.
Key Responsibilities
- Design, prototype and deliver production software across the lending platform.
- Build AI-powered products using LLMs, RAG, agents and model APIs.
- Develop AI tools for brokers and underwriters, including decision-support systems and workflow automation.
- Influence architecture and technical direction through practical experimentation and delivery.
- Build scalable, secure APIs, web applications and AWS cloud-native services.
- Develop robust approaches to AI evaluation, observability, safety and cost management.
- Raise engineering standards through mentoring, pairing and code reviews.
- Work closely with technical and non-technical stakeholders to turn complex problems into simple, practical solutions.
Tech Stack
Python, React, TypeScript, Django, FastAPI, PostgreSQL, AWS, Docker, REST APIs, Git and CI/CD.
The AI stack includes LLMs, RAG, vector search and embeddings, agentic workflows, prompt engineering, structured outputs, LLM evaluation and Amazon Bedrock.
What We’re Looking For
We’re looking for someone who combines strong engineering fundamentals with genuine hands-on AI experience.
You’ll ideally have:
- Expert-level Python development skills.
- Strong experience with React and TypeScript.
- Strong experience with Django and/or FastAPI.
- Demonstrable technical leadership through influence, delivery and mentoring.
- Hands-on experience building and taking AI/LLM systems into production.
- Experience working with modern AI patterns such as RAG, agents, embeddings and LLM APIs.
- A pragmatic engineering mindset focused on simplicity, maintainability, security and reliability.
Why Join?
This is an opportunity to join a rapidly growing FinTech where AI is genuinely central to the product strategy, rather than simply being an experimental side project.
You’ll have significant influence over the technical direction of the business while remaining hands-on with the technology. Most importantly, you’ll have the opportunity to take emerging AI technologies from initial prototype through to real-world production, directly impacting how the next generation of mortgage lending operates.
