Settlement platform, rebuilt while running
A 19-year-old batch settlement core replaced with an event-sourced ledger — with no unplanned outages and no big-bang cutover.
- Year
- 2025
- Duration
- 11 months
- Team
- 6 engineers, 1 designer
- Sector
- Financial services
The problem
A 19-year-old settlement core, batch-bound and unable to clear intraday. Reconciliation ran for six hours overnight, and any failure pushed the bank past its regulatory window. Three prior vendors had attempted the migration and stopped.
What we did
We put a strangler facade in front of the legacy core and built an event-sourced ledger behind it. Instrument classes moved across one at a time, with both systems computing every settlement in parallel and reconciling continuously until the new ledger had earned the traffic.
Where it landed
Intraday settlement in ninety seconds, a ledger the risk team can query directly, and a legacy core switched off eleven months after kick-off without a single unplanned outage.
“Three vendors told us this would take three years and break everything. Codeaex did it in eleven months with zero unplanned outages.”
Eleanor Vance
CTO, Meridian Bank
Tell us what is breaking.
Send the problem, not a polished brief. A principal engineer reads every enquiry and replies within two working days with a real technical opinion.
- Reply from an engineer, not a salesperson
- Fixed scope and price before any build starts
- Your code, your cloud, your repo — from day one