Ledger-Core Banking & Real-Time Market Systems

The challenge

Fintech systems fail differently from other software. A slow web page is an annoyance; a ledger that is off by a cent is a liability. Our work in this space covers two demanding shapes of system: banking platforms, where every balance must be provable, and real-time market systems, where data arrives continuously over live feeds and correctness has to survive reconnects, retries, and partial failures. This work is confidential, so this case study describes the capability, not the clients.

What we built

On the banking side, we build platforms on an open-source double-entry ledger core: account structures, transaction flows, and the operational tooling around them. The governing rule is reconciliation-first — internally derived numbers are treated as untrusted until they tie out against the authoritative record. When the two disagree, the derived number is presumed wrong until proven otherwise. That rule shapes everything from schema design to reporting.

On the market side, we build real-time market-data and trading systems that operate on regulated US venues: resilient WebSocket pipelines that keep state correct across disconnects, order-lifecycle tracking that reflects what the venue actually confirmed rather than what was requested, and continuous reconciliation of positions and balances against venue records. Operational dashboards give operators a live, truthful picture of the system — what is open, what has settled, and what needs attention.

Across both, we apply the same change discipline we use everywhere: every production change is planned, applied, verified, and documented with evidence.

The outcome

These systems run in production. We do not publish client names, venue names, or performance figures — in this domain, discretion is part of the engineering. What we can offer is the pattern itself: if your product moves money or reacts to live market data, we build it so the numbers are provable, the failure modes are handled, and the people operating it can always see what is true.