Senior Backend Engineer (L5) -Payments

About Us OpenFX is on a mission to move money as freely as data, unrestricted by time zones, banking hours, or legacy systems. We are building the infrastructure that will power the next generation of cross-border payment systems for institutions. The team's execution has been exceptional, and we're scaling at a remarkable pace. Our stellar early team comes with experience in companies like J.P. Morgan, Goldman Sachs, FalconX, PayPal, Affirm, Polygon, Kraken, Nium & others. We're backed by Accel, Lightspeed, NfX and other top-tier investors. Role Overview We're hiring a Staff Software Engineer for our Payments team. This is the senior-most individual contributor role on the systems that move money across borders — payment orchestration, corridor and partner integrations, FX and quoting, the payment lifecycle from initiation to settlement confirmation, and the regulated controls (safeguarding, transaction monitoring) that our EU licenses demand. It is a hands-on technical leadership role on the money path, where a new corridor is only as good as its failure handling, and a regulatory control is only as good as the evidence it produces. The cost of a defect is measured in real money, stuck customer payments, or a finding from a regulator. You will report to an Engineering Manager and work closely with engineers, product, compliance, and partnerships across the company. You will set the technical direction for payments, lead the hardest corridor and orchestration problems, and raise the bar for how we build. This role requires someone who has built and operated payment or other correctness-critical systems in production, ideally against external partners whose behavior you do not control. If your experience is limited to systems where occasional data inconsistency is acceptable, where every dependency was internal and well-behaved, or where you have not owned something end to end for a meaningful stretch, this will be a stretch. Key Responsibilities Own the technical direction for payments: payment orchestration, corridor and partner integrations, FX and quoting, lifecycle modelling (statuses, webhooks, returns, recalls), and settlement confirmation. Design the corridor expansion architecture: turn new-corridor launches (EUR, MXN, COP, AED, and beyond) from bespoke integration projects into configuration-driven, repeatable capability — standardized partner adapters, corridor config over code, and a rigorous definition of launch-ready. Lead the engineering of regulated controls: safeguarding flows (segregation, sweeps, coverage reconciliation) and transaction monitoring pipelines, built so that every control produces an audit trail that stands up to regulators and auditors. Define and maintain the standards for money-path code — idempotency, exactly-once effects, consistency guarantees under partner failure, safe retries against external systems, and backward-compatible API evolution. Own resilience against partners:…