- Money movementBoundaries
- ReversibleCutover
- One sourceBalances
How we approach it
We decompose along money-movement boundaries — posting versus settlement, products that never share a balance — with explicit contracts between them. An event log is introduced where replay and audit justify it, never by default. Balances derive from one source of truth, and cutovers run through dark reads, shadowed writes, and a reversible switch, so operations stay uneventful.
