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OpenFX is building infrastructure for next-generation cross-border payment systems for institutions, with a mission to move money as freely as data across time zones and legacy systems. The company is backed by top-tier investors including Accel, Lightspeed, and NfX, and the team includes veterans from J.P. Morgan, Goldman Sachs, FalconX, PayPal, Affirm, Polygon, Kraken, and Nium.
You will join the Payments team as a Senior Backend Engineer (L3), owning critical systems on the money path. Your responsibilities span the full lifecycle: payment initiation, routing to partners, lifecycle state management, settlement tracking, and reconciliation. You'll design for correctness under failure—idempotency, safe retries, exactly-once effects on money state, and graceful degradation when partners are down.
Key areas of ownership include:
- Backend of payment flows across API and GUI surfaces
- Partner integrations for new corridors (EUR, MXN, COP, AED, and beyond)
- Regulated controls: safeguarding flows and transaction monitoring pipelines with audit trails
- Client-facing surfaces: payment tracking, status views, and reporting dashboards
- Instrumentation and observability of the money path to detect issues before clients report them
- End-to-end feature ownership rather than stopping at backend boundaries
You'll work full-stack, building both backend systems and dashboard views, and collaborate closely with Product, Operations, and Compliance. You'll mentor L1/L2 engineers, drive code review and design feedback, manage tech debt, and participate in on-call rotations. The role demands accountability for adoption and product impact, not just delivery.
Must-haves: 5–7 years building production backend systems with depth in server-side and distributed systems; proven payments or fintech background (payment gateway, PSP, neobank, or cross-border payments company); expert-level TypeScript and Node.js; strong PostgreSQL data modeling and query skills; sound instincts for correctness under failure (idempotency, retries, partial failures, ordering); hands-on experience integrating external partner APIs; experience with asynchronous processing (queues, jobs, workflow engines); and automated testing expertise including integration tests.
