Live demo

Open this page in two tabs. Click Emit event (top-right of the grid) — a new row appears live in both tabs with no reload. The grid is an SSE feed; the button publishes the feed's watch scope and the server pushes the fresh page to every connected grid.

refreshInterval Watch scopes Server re-renders truth

Live HTML

"Live" usually means a client-side store that reconciles websocket messages into a virtual DOM — a second state architecture running alongside the server. Semitexa's Live HTML keeps the server as the single source of truth: it re-renders the region and the page swaps the new HTML in.

Cadence or invalidation — same model

Add refreshInterval to a region and the server re-runs its pipeline and streams fresh HTML on a timer. Add a watch scope instead and the region re-renders whenever a domain write touches that scope. Either way the runtime swaps the new HTML in place over the same SSE stream that delivered the first paint.

The live grid in this handbook works exactly this way: emit an event and every open tab updates with no reload. Live behaviour is a property of a region's contract, not a parallel architecture — there is no client store to keep in sync and no reconciliation layer to debug. The server owns and re-broadcasts truth, just as it did for the first byte.

1#[AsSlotResource(slot: 'inventory-summary', deferred: true, refreshInterval: 5)]2final class InventorySummarySlot { /* server re-renders every 5s, swaps HTML in place */ }

#[AsSlotResource(slot: 'inventory-summary', deferred: true, refreshInterval: 5)]
final class InventorySummarySlot { /* server re-renders every 5s, swaps HTML in place */ }

1// or event-driven: re-render whenever a domain write touches the scope2#[WatchScopes('platform_live_events')]3final class ShowcaseLiveFeedPayload implements SseCollectionFeedPayloadInterface { /* … */ }

// or event-driven: re-render whenever a domain write touches the scope
#[WatchScopes('platform_live_events')]
final class ShowcaseLiveFeedPayload implements SseCollectionFeedPayloadInterface { /* … */ }

How it works

Add refreshInterval — or a watch scope — to a slot resource and the server re-runs its pipeline and streams fresh HTML on a cadence or on invalidation; the runtime swaps it in place over the same SSE stream. The grid below is live this way: emit an event and every open tab updates with no reload.

Why it matters

Live behaviour becomes a property of a region's contract, not a parallel architecture. There is no client store to keep in sync, no reconciliation layer to debug — the server owns and re-broadcasts truth, exactly as it did for the first paint.