Full Stack Developer - Fintech
Do you want to build the next generation of a well-functioning fintech platform - and help set the standard for how we build with AI?
Flex Funding is an established Scandinavian crowdlending platform that helps SMEs access flexible financing in Denmark and Norway through a crowd of 4,000+ investors. We are scaling both geographically – launching in Sweden – and in terms of new financing solutions.
We are now expanding the platform significantly, both commercially and in how we develop. That is why we are looking for one of the strongest full stack developers out there – someone who both wants to build product and raise the bar for how we build.
About the role
You will be a key player in a small, experienced team with backgrounds in banking, fintech, and product development. On a daily basis we work with complex credit, payment, and partner flows.
The role has two equally important sides:
You build: end-to-end solutions on our platform – from new features and services to improving existing flows, primarily on the backend but also frontend where it makes sense.
You improve: how we develop, making AI a natural part of the entire lifecycle – from coding and testing to refactoring, documentation, and knowledge sharing.
You will work closely with the business, compliance, and partners, and have strong influence on how we move from “stable and well-functioning” to “fast, AI-enabled, and significantly more scalable”.
Current setup
Backend: C#, ASP.NET Core, REST/GraphQL APIs, Azure SQL, modular architecture, and secure, auditable financial workflows.
Frontend: Vue / NuxtJS, SPA development, API-driven user interfaces.
Your responsibilities
Take end-to-end ownership of solutions: from early sketches and prototypes to robust, production-ready systems.
Develop and improve core platform functionality (loans, payments, partners, back office).
Build new products and further develop our existing solutions.
Design and implement AI-first workflows in development (code, test, refactoring, documentation) and create “golden paths” the rest of the team can follow.
Reduce complexity in existing components and make it faster and safer to build new functionality without breaking changes.
Ensure knowledge is embedded in code, tests, and documentation to reduce key-person dependency.
Who you are
We are looking for a strong builder profile with an AI mindset and at least ~5 years of experience building and operating full stack solutions in production.
You will recognise yourself in most of this:
Strong full stack foundation: you are comfortable in both backend and frontend and have built and shipped production systems.
Ownership and leadership: you have previously built substantial solutions from scratch (e.g. startup, scale-up, or your own projects) and taken responsibility for both solution and outcome.
System and data thinking: you can design data models, think in architecture, data flows, and trade-offs – and know when event-driven makes sense and when a simpler approach is better.
AI as a tool, not a gimmick: you already use AI development tools actively and want to help set a new standard for how a small team can build fast, efficiently, and with high quality.
Critical technical judgment: you can spot weaknesses in an existing architecture and propose concrete, pragmatic improvements.
Communication: you can explain complex technical decisions clearly – both to other engineers and to business stakeholders.
It’s a plus if you have experience with
Fintech, crowdlending or other credit and payment solutions.
API design and third-party integrations.
Working in regulated environments with supervision, compliance, and reporting requirements.
CI/CD, test automation, and modernising existing codebases.
Why Flex Funding?
A well-functioning platform that already helps businesses access financing every day.
A small, experienced team with short path from idea to decision – you feel the impact of your work quickly.
Significant influence on architecture, tech stack, and our AI strategy in practice.
The opportunity to build a lot, while also shaping how we as a team build going forward.
A Scandinavian fintech in growth – with new markets and products on the way.
Practical details
Full-time position.
Location: CPH Fintech Lab
Start date: As agreed – preferably as soon as possible.
How to apply
Send your CV and a short motivated application to Gunvor Overbye at gunvor.overbye@flexfunding.com. We review applications on an ongoing basis.