Senior Software Engineer (E1BAD0F)

Referment is working with an FCA-regulated cross-border payments and foreign exchange business that builds and runs its own banking platform. Its Banking and FX team owns payment processing, FX pricing and trading, the ledger, reconciliation, bank integrations, FIX engine connectivity, payment compliance and the client portal — the movement of client money end to end, and everything clients see while it happens.You'll build services in .NET 10 on Azure, mostly asynchronous flows that have to stay correct when a banking partner times out halfway through or when the same message arrives twice. Because the platform is end-to-end, the work spans all of it rather than one corner: payments, FX, the ledger, reconciliation, integrations, compliance and the portal. Wherever it lands, getting it right beats getting it out. You make the design calls in your domain and argue them out with the team — services stay with the engineers who wrote them, so you're trusted to build them your way, run them and own them.The RoleDesign, build and run services in .NET 10 on Azure, owning them from first commit through to production support.Build asynchronous flows that stay correct under partial failure, timeouts, retries and duplicate delivery.Work across the platform: payment processing, FX pricing and trading, the ledger and reconciliation, bank and scheme integrations, FIX connectivity, payment compliance and the client portal.Integrate with banking partners and payment schemes, including the parts of those integrations nobody documents.Make the architectural calls in your domain, write them down and defend them in front of the team.Build in security, availability, reliability and observability from the start, and instrument your services so the answer to what's happening is already in a dashboard.Use AI tooling well — AI coding assistants are in daily use here, and you're expected to judge where they earn their place and where they don't.Review code, raise the standard around you and help less experienced engineers improve.What We're Looking ForPlenty of .NET behind you, and experience running your own services in production rather than shipping features into someone else's.Production experience on cloud platforms — Azure ideally, but similar work on AWS or GCP is just as valuable.Comfort with asynchronous, event-driven systems and their awkward parts: idempotency, ordering, retries, poison messages, and exactly-once as a promise nobody can keep.Security, availability, reliability and observability built in from the start rather than bolted on at the end — you think about who can reach what, know how your service behaves when a dependency disappears, and instrument it accordingly. Grafana and Application Insights are used here, and because the business holds client money, this is the job rather than a preference.Real experience building software with AI, not just an interest in it.Strong SQL Server, including query and schema work under real load, and strong familiarity with code-first ORMs — a bonus if that's EF Core.Solid testing instincts and the ability to say what a piece of code is actually protected against.Comfortable working somewhere regulated, where changes to how money moves need evidence behind them.Clear communication with engineers and non-engineers, and the willingness to disagree, then commit once the call is made.Useful, But Not RequiredPayment processing systems, double-entry ledgers, FX products and pricing, reconciliation and breaks, payment compliance, bank and scheme integrations, or FIX protocol and market connectivity. If you've done any of it, say so — if you haven't, the team would rather teach you that than compromise on the engineering.This could suit a senior engineer who has run production services on Azure or another cloud and wants genuine ownership across a money-movement platform, including people from payments, banking or trading backgrounds who want to work closer to FX, ledgers and settlement. The role is hybrid, with two to three days a week in the London office.#Referment