Field Notes / Resilience & Security
The throughput target no customer needed
A field report about sizing a system for a demand assumption that the business never forced itself to validate.
Architecture can be internally sound and still protect the wrong business assumption.
First-hand context
I led the build of a core banking platform around an extreme throughput target. The engineering held up. The demand did not.
Decision record
The decision and its trade-off
We optimized the bespoke path before making the demand side carry a dated burden of proof.
What can be inspected
The source archive preserves the design rationale, the unused capacity, and the cheaper path I argued against.
What failed or remains uncertain
The exact throughput figures stay out of this draft until a scoped claim is approved.
Field rule
A reusable principle
Write down the demand assumption, the date that tests it, and the decision that follows if it fails.