The Sim Book

A guide to building and testing distributed systems with moonpool, a deterministic simulation framework for Rust.

Moonpool brings together ideas from FoundationDB, TigerBeetle, and Antithesis into a single library-level framework. Write your system once with provider traits, then run it against a simulated world that is deliberately worse than production. Same code, different wiring. No #[cfg(test)]. No mocks.

This book covers the philosophy, the architecture, and the practical details of building simulation-tested distributed systems.