---
title: Concepts
---

Chronicle concepts are documented once in the shared Chronicle docs. The
Kotlin client pages only cover Kotlin and Java setup, annotations, and API
details.

Use these shared pages for the concepts:

- [Events](/chronicle/concepts/event/)
- [Event sources](/chronicle/concepts/event-source/)
- [Observers](/chronicle/concepts/observers/)
- [Read models](/chronicle/read-models/)
- [Projections](/chronicle/projections/)
- [Reactors](/chronicle/reactors/)
- [Reducers](/chronicle/reducers/)

Shared examples use synchronized C#, Kotlin, Java, Elixir, and TypeScript
tabs when the client APIs differ.

For JVM-specific syntax, see the [annotation
reference](/chronicle/clients/kotlin/reference/annotations/).