Fintech · Platform
Re-architecting a real-time ledger to scale under sustained load.
- Fintech
- Multi-month build
- Senior, founder-led
- New build → operate
The problem
The existing monolithic ledger degraded under sustained transaction load and could not close the day on time. Off-the-shelf payment platforms could not model the required settlement rules, and correctness was non-negotiable — every entry has to balance.
The engineering challenge
Sustained double-entry correctness under heavy transaction volume, with an auditable history and a zero-downtime migration off the live system that was still processing money.
The solution
We designed an event-sourced core with an append-only journal, sharded by account range, and a projection layer for balances and reporting. Writes are idempotent and ordered per account; reconciliation runs continuously rather than as an overnight batch. We cut the migration over shard by shard, dual-writing until each was proven.
Architecture
Technology
Chosen for this workload — the load, the team, and the ten-year cost.
The result
- Sustained
- Lower p95
- Zero-downtime
Start
Have a system like this?
Tell us the hard part — we'll come back with a technical point of view.
Or email hello@iyc.global