Senior Full-Stack Engineer - Credit Cards

Senior Full-Stack Engineer - Credit Cards Hybrid in London, United Kingdom We’re looking for a Senior Full-Stack Engineer. You’ll build features on iwoca’s business credit card and own each one from the first line of code to the moment a customer makes their first spend. The company Small businesses move fast. Opportunities often don’t wait, and cash flow pressures can appear overnight. To keep going, and growing, SMEs need finance that’s as flexible and responsive as they are. That's why we built iwoca. Our smart technology, data science and five-star customer service ensures business owners can act with the speed, confidence and control they need, exactly when it's needed. We’ve already cleared the way for 100,000 businesses with more than £5 billion in funding. Our passionate team is driven to help even more SMEs succeed, through access to better finance and other services that make running a business easier. Our ultimate mission is to support one million SMEs in their defining moments, creating lasting impact for the communities and economies they drive. The team iwoca launched its business credit card in 2026. It gives small businesses a fast, flexible way to pay for what they need and control their cash flow, alongside iwoca’s loans. The card is a core part of iwoca’s long-term growth. The Credit Cards team builds what business owners use to sign up, get their card, and manage it, on the web and in the iwoca Mobile App. It’s cross-functional – engineers collaborate with product and design. The role As a senior full-stack engineer, you’ll work mostly on the backend, and build the frontend for your features too. Ownership. You’ll shape what the team builds next, starting from what customers need. You’ll decide how each of your features works, from the data model and API to how you test, release, and monitor it. Impact. Business owners use your work every time they check their cashback, set spend controls, or freeze a lost card. The team releases often, and your changes reach them quickly. Variation. You’ll write Python and FastAPI services backed by PostgreSQL, and React and TypeScript for the web. You’ll also work in React Native on the iwoca Mobile App, and on the Credit Cards CRM that operations staff use, when a feature needs it. Card expertise. You’ll learn how card transactions work – from the card processor to the card scheme – alongside the engineers who build iwoca’s payments platform. AI-first engineering. You’ll build with AI coding tools as standard. On the iwoca Mobile App, for example, the team writes a spec for each feature and reviews it before building it with Claude Code. The requirements Essential: Backend engineering. You've built well-tested Python services for customer-facing products, and kept them working once people relied on them. Data models and APIs. You've designed relational data models, ideally in PostgreSQL, and built and integrated APIs. Frontend. You've written enough React and TypeScript to build and ship customer-facing features. Product ownership. You've taken features from an idea to production and owned them once they were live. You've challenged a plan when it didn't meet a customer need, and offered a better one. AI leverage. You've built agentic workflows, or used AI to scale your engineering output beyond what you could deliver alone, at work or in your own projects. You judge when to use it and when not to, and you check its output before it reaches production. Communication. You write and speak clearly, directly, and concisely. You adapt technical detail to your audience. Bonus: Mobile. You've developed iOS or Android app features, ideally in React Native. Fintech. You've worked on financial products, especially card payments. FastAPI. You've built and run production services with FastAPI. Internal tools. You've written software for operations or support staff. The salary We expect to pay from £80,000 to £90,000 fo