Full Stack Engineer

Full Stack Engineer – Portfolio Intelligence Fintech

London (hybrid flexibility) | £80,000–£100,000 + equity | Permanent

My client is a funded, early-stage fintech building portfolio intelligence software for corporate treasuries, stablecoin issuers and financial institutions. Their platform brings portfolio analysis, risk management, scenario modelling and investment comparison into one product, helping teams decide where their cash and digital assets should sit.

The founding team comes from leading hedge funds, global banks and blockchain infrastructure. The product is live, with paying clients across banking, stablecoins and corporate treasury, and they’ve just secured further funding to grow the engineering team.

They’re hiring a Full Stack Engineer to work directly with the CTO, owning features end to end and helping shape the product at an early stage.

What you’ll do

• Build React and TypeScript interfaces for portfolio analysis, scenario modelling and investment decisions, with real care for the user experience
• Develop the Python (FastAPI) services, APIs and data integrations behind them
• Take features from idea to production: make the architecture calls, ship, and own the result
• Build AI into the product in ways that are actually useful, from exploring a portfolio to comparing scenarios

What they’re looking for

• 3+ years building web applications commercially, with strong React and TypeScript and practical Python backend experience
• Experience below the framework: async workflows, data consistency, partial failures, and what to do when connected services disagree
• AI-native: you get real leverage from agents and AI tools, but you still check the output and understand the code
• A track record of owning shipped features and explaining the trade‑offs you made
• Breadth over specialism: you’ve worked across the stack, ideally in a startup or scale‑up
• Curiosity about finance. Fintech payments investing or crypto experience is a plus, but not essential

What’s on offer

• Company‑paid ChatGPT Pro or Claude Pro subscription
• Modern office in central London
• Real ownership and a direct line to the CTO in a small, technical team