llms.txt

Real-time Chat

An example of building a simple in-memory chat using a hydrated island and the built-in WebSocket support in Bun. The server stores a bounded message history and replays it to new connections; ws.publish() broadcasts each message to all clients. Messages over 4 KB are rejected, frames over 8 KB are dropped by Bun before they are buffered, and a per-client window closes anyone sending more than 20 messages per 10 seconds. Open this page in two tabs to see them sync in real time.

Chat

Hello friend! How are you?

View source on GitHub

<script>
  import ChatWidget from './ChatWidget.svelte';
</script>

<ChatWidget mochi:hydrate />

More demos

Data Loading How server-side data loading works — fetch on the server, cache with MochiCache, and render at request time. Request ID How request IDs work — every request gets a UUID v7 on getRequestContext().requestId that rides every lifecycle event for correlation. Send Email How sending email works — dispatch through Mochi.email() and read it back in the /_mochi/email dev outbox.