Hello World (Effect)

Minimal counter actor built with the Effect SDK for Rivet Actors.

Getting Started

git clone https://github.com/rivet-dev/rivet.git
cd rivet/examples/hello-world-effect
npm install
npm run dev

In a separate terminal, run the client against the server:

npm run client

Features

• Effect-native actors: Define an actor with Actor.make and implement it with toLayer, returning action handlers from an Effect wake scope
• Typed action protocols: Increment and GetCount are standalone Action.make values with Schema payloads and successes validated end to end
• Typed errors across the wire: Increment declares a NegativeAmountError that arrives on the caller as a real tagged instance, caught with Effect.catchTag
• Persistent state: The counter value lives in persisted actor state, accessed through a SubscriptionRef-like State API
• Events: Each increment broadcasts the new count to every connected client

Implementation

The actor is split into a public contract and a server-only implementation:

• Contract (src/actors/counter/api.ts): Declares the Counter actor and its actions
• Implementation (src/actors/counter/live.ts): Implements the wake scope, state schema, and action handlers
• Server (src/main.ts): Composes the actor layer and serves it with Registry.serve
• Client (src/client.ts): An Effect client using the typed Counter.client accessor

Resources

Read more about actions, state, events, and the Effect quickstart.

License

MIT