The Umari Book

Status: Draft.

This book is the official guide to building event-sourced systems with Umari. It covers concepts, patterns, API reference, and operations — everything you need to go from zero to production.

Who this book is for

You should be comfortable with Rust. Prior event sourcing experience helps but is not required — the first part explains the concepts from scratch.

How to read this book

• Part 1 — Concepts: Read straight through. These chapters establish the mental model.
• Part 2 — Building Blocks: Read straight through. You’ll use every concept here.
• Part 3 — Module Types: Reference each chapter as you build that module type.
• Part 4 — Working with Umari: Practical patterns, project structure, and API reference.
• Part 5 — Runtime & Operations: Read when deploying or debugging.

Code examples follow current API conventions.

Conventions

• Crate names: umari refers to the SDK crate (crates/umari). umari-runtime refers to the runtime. Module crates use kebab-case names.