Senior Full-Stack Engineer – FinTech & Payments
Remote (UK/EU – Time Zone Overlap)
£90,000–£110,000 + Equity Participation + Fully Remote + Holiday Flexibility + High Autonomy + AI-First Environment
Are you a Senior Full-Stack Engineer with experience building payment platforms, escrow systems or marketplace financial infrastructure, looking to join an ambitious AI-native startup developing the future operating system for UK property maintenance? Do you want the opportunity to take founding ownership of an entire payments domain, designing and delivering mission-critical escrow, payouts, ledgering and reconciliation systems where correctness, auditability and scalability are non-negotiable?
On offer is the opportunity to join an innovative UK PropTech scale-up building a new AI-powered platform for the property maintenance sector. With a £30m waitlist behind the platform and ambitious growth plans, this is a genuine founding engineering position responsible for building the financial infrastructure that underpins how money moves through the platform.
In this role, the successful Founding FinTech Engineer will become the single accountable owner of the Money Engine, taking responsibility for payments, escrow, review-gated contractor payouts, disputes, financial ledgering, reconciliation and third-party financial integrations. You will work directly with the CTO within a small autonomous engineering environment, with significant ownership over architecture, technical decisions and the long-term development of the domain.
The ideal candidate will be a hands-on engineer with strong experience across FinTech, payments or financial transaction systems. Experience could include marketplace payments, escrow, PSP integrations, ledgering, reconciliation or similar money-movement infrastructure. Exposure to platforms such as Stripe, Unipaas, Adyen or Mangopay would be highly advantageous, alongside a strong understanding of building reliable and auditable financial systems.
The Role:
• Take founding ownership of the platform's Money Engine
• Build escrow holds and review-gated contractor payout flows
• Develop dispute, refund and payment resolution workflows
• Build append-only financial ledger receipts and audit trails
• Deliver daily reconciliation against payment provider settlement data
• Build and maintain PSP and third-party financial integrations
• Work directly with the CTO with significant architectural autonomy
The Person:
• Full-Stack Engineer with FinTech, payments or financial systems experience
• Experience with marketplace payments, escrow or money-movement systems
• Exposure to PSP integrations such as Stripe, Unipaas, Adyen, Mangopay or equivalent
• Strong Postgres experience including ledgering, idempotency and transactional patterns
• Good understanding of transaction integrity, webhooks, reconciliation and auditability
• TypeScript/Node.js and/or Python backend engineering experience
Keywords: FinTech Engineer, Founding Engineer, Full Stack Engineer, Senior Software Engineer, Payments Engineer, TypeScript, Node.js, Python, FastAPI, Stripe, Unipaas, Adyen, Mangopay, Escrow, Marketplace Payments, Payment Integration, Payment Gateway, PostgreSQL, Ledger, Reconciliation, Webhooks, Idempotency, Financial Transactions, FinTech, Payment Platform, Remote
