Case study // Northwind Treasury
Multi-rail FX routing across 31 corridors
Built a cost-aware router that picks the cheapest compliant rail per payment, per second, across 31 currency corridors.
FX cost
−41 bps
Routing decision
4ms
Stack
Rust · gRPC · SWIFT gpi · RTP · Redis
01 — Challenge
Northwind routed every cross-border payment over SWIFT by default, overpaying on corridors where local instant rails were cheaper and faster.
02 — Architecture
A live quote mesh polls 9 liquidity providers and caches spreads with 250ms freshness guarantees.
Sanctions and corridor policy are evaluated as code before any route is eligible.
Every routing decision is recorded with its counterfactual for treasury audit.
03 — Outcome
Average FX cost fell 41 bps across $62B of annual volume, and median delivery moved from T+1 to 38 seconds.