Core

The core is Arc’s frontend layer beneath React — the framework-agnostic TypeScript that the React hooks build on. Most apps consume it indirectly through React; reach for it directly when you’re working outside React (a service layer, a worker, a vanilla-TS integration) or you need lower-level control over how commands and queries execute.

Topic	What it covers
Commands	Instantiating and executing commands without React — the runtime behind the hooks.
Queries	Retrieving data and subscribing to observable queries at the core level.
Validation	The validation rules and results that flow through commands and queries.
Identity	The user-context primitives the higher layers expose.
Messaging	The messaging and communication patterns Arc uses under the hood.

Building UI? You almost certainly want React instead — it wraps everything here in hooks.