System
Funds Authorization.
Banking core ISV.
A two-tier authorization service rebuilt for cloud.
Without placing a database in the critical path.
Constraint
Each authorization fetches data across a network.
Each fetch is synchronous.
Each fetch is variable.
Each fetch is on a millisecond budget.
Faster databases. Faster networks. Faster servers.
None change the slope.
Rumi changes the slope.
Foundation
State and execution co-located.
Data is local. Always.
Authorization compute and customer balance share the same memory space.
Persistence, messaging, and recovery are platform concerns.
Developers write plumbing-free business logic.
The fetch is effectively free.
Outcomes
Transactions per CPU core rose 55×.
Latency fell 60×, from over 300 ms to 5 ms.
$1M became $9k.
At 60,000 requests per second.
300 servers became 4.
Rumi processing itself: sub-millisecond.
Initial port in 3 weeks.
Cutover with no client API changes.
Zero loss recovery across every failure mode.