Loom
(2026)
Real-time geo-dispatch: it matches 5,000 simulated drivers in milliseconds and never double-books one. Positions stream in over WebSockets into a Redis index built on H3 hexagonal cells; the matcher runs an atomic claim and an offer cascade so two riders can never win the same driver.
A TypeScript monorepo with the parts a dispatch system actually needs: a trip state machine with a transactional outbox, a janitor that recovers claims stranded by a crash, a GCRA rate limiter, a sliding-window surge engine per cell, a CQRS read model streaming over server-sent events, and a deck.gl dashboard to watch it happen.
Proven under load rather than described: zero double-bookings across 200 concurrent claims on the same driver, around 214 matches per second, 229 tests. The city is simulated; the engineering is not.
