System
Exposure Monitor.
Global hedge fund.
Real-time consolidated risk across every portfolio manager, every order, every trade.
Tens of microseconds. On two servers.
Constraint
Portfolio managers act independently.
The fund-level imbalance is invisible.
A consolidated tally must update faster than the desk can use it.
Double-digit microseconds.
No round-trip fits.
The fund started building the substrate themselves.
It outweighed the risk logic.
Rumi is the substrate.
Foundation
State and execution co-located.
Data is local. Always.
Tally compute, tally storage, tally serving, tally streaming.
Same node. Same data.
Persistence, messaging, and recovery are platform concerns.
Developers write plumbing-free business logic.
One node holds the whole pipeline.
Outcomes
Wire-to-wire tally latency fell 20×.
From over 1 ms to under 50 microseconds.
6 million orders per second.
Two servers.
Fewer than 4 threads each.
Linear horizontal scaling with cluster partitions.
Shipped in 3 months.
Zero loss recovery across every failure mode.