diff --git a/src/components/DynamicWindowTitle.tsx b/src/components/DynamicWindowTitle.tsx
index 834bed7..0ab9d65 100644
--- a/src/components/DynamicWindowTitle.tsx
+++ b/src/components/DynamicWindowTitle.tsx
@@ -23,9 +23,7 @@ import {
 import { getEventDisplayTitle } from "@/lib/event-title";
 import { UserName } from "./nostr/UserName";
 import { getTagValues } from "@/lib/nostr-utils";
-import { getLiveHost } from "@/lib/live-activity";
-import type { NostrEvent } from "@/types/nostr";
-import { getZapSender } from "applesauce-common/helpers/zap";
+import { getSemanticAuthor } from "@/lib/semantic-author";
 // import { NipC7Adapter } from "@/lib/chat/adapters/nip-c7-adapter";  // Coming soon
 import { Nip29Adapter } from "@/lib/chat/adapters/nip-29-adapter";
 import type { ChatProtocol, ProtocolIdentifier } from "@/types/chat";
@@ -37,31 +35,6 @@ export interface WindowTitleData {
   tooltip?: string;
 }
 
-/**
- * Get the semantic author of an event based on kind-specific logic
- * Returns the pubkey that should be displayed as the "author" for UI purposes
- *
- * Examples:
- * - Zaps (9735): Returns the zapper (P tag), not the lightning service pubkey
- * - Live activities (30311): Returns the host (first p tag with "Host" role)
- * - Regular events: Returns event.pubkey
- */
-function getSemanticAuthor(event: NostrEvent): string {
-  switch (event.kind) {
-    case 9735: {
-      // Zap: show the zapper, not the lightning service pubkey
-      const zapSender = getZapSender(event);
-      return zapSender || event.pubkey;
-    }
-    case 30311: {
-      // Live activity: show the host
-      return getLiveHost(event);
-    }
-    default:
-      return event.pubkey;
-  }
-}
-
 /**
  * Format profile names with prefix, handling $me and $contacts aliases
  * @param prefix - Prefix to use (e.g., 'by ', '@ ')
@@ -474,8 +447,21 @@ function useDynamicTitle(window: WindowInstance): WindowTitleData {
   const countHashtags =
     appId === "count" && props.filter?.["#t"] ? props.filter["#t"] : [];
 
-  // Zap titles
-  const zapRecipientPubkey = appId === "zap" ? props.recipientPubkey : null;
+  // Zap titles - load event to derive recipient if needed
+  const zapEventPointer: EventPointer | AddressPointer | undefined =
+    appId === "zap" ? props.eventPointer : undefined;
+  const zapEvent = useNostrEvent(zapEventPointer);
+
+  // Derive recipient: use explicit pubkey or semantic author from event
+  const zapRecipientPubkey = useMemo(() => {
+    if (appId !== "zap") return null;
+    // If explicit recipient provided, use it
+    if (props.recipientPubkey) return props.recipientPubkey;
+    // Otherwise derive from event's semantic author
+    if (zapEvent) return getSemanticAuthor(zapEvent);
+    return null;
+  }, [appId, props.recipientPubkey, zapEvent]);
+
   const zapRecipientProfile = useProfile(zapRecipientPubkey || "");
   const zapTitle = useMemo(() => {
     if (appId !== "zap" || !zapRecipientPubkey) return null;
diff --git a/src/components/ZapWindow.tsx b/src/components/ZapWindow.tsx
index 2580eff..aea9b09 100644
--- a/src/components/ZapWindow.tsx
+++ b/src/components/ZapWindow.tsx
@@ -49,6 +49,7 @@ import {
 } from "@/lib/create-zap-request";
 import { fetchInvoiceFromCallback } from "@/lib/lnurl";
 import { useLnurlCache } from "@/hooks/useLnurlCache";
+import { getSemanticAuthor } from "@/lib/semantic-author";
 
 export interface ZapWindowProps {
   /** Recipient pubkey (who receives the zap) */
@@ -98,8 +99,10 @@ export function ZapWindow({
     );
   }, [eventPointer]);
 
-  // Resolve recipient: use provided pubkey or derive from event author
-  const recipientPubkey = initialRecipientPubkey || event?.pubkey || "";
+  // Resolve recipient: use provided pubkey or derive from semantic author
+  // For zaps, this returns the zapper; for streams, returns the host; etc.
+  const recipientPubkey =
+    initialRecipientPubkey || (event ? getSemanticAuthor(event) : "");
 
   const recipientProfile = useProfile(recipientPubkey);
 
diff --git a/src/components/nostr/kinds/BaseEventRenderer.tsx b/src/components/nostr/kinds/BaseEventRenderer.tsx
index 9b4986a..1c43ca3 100644
--- a/src/components/nostr/kinds/BaseEventRenderer.tsx
+++ b/src/components/nostr/kinds/BaseEventRenderer.tsx
@@ -21,6 +21,7 @@ import { getSeenRelays } from "applesauce-core/helpers/relays";
 import { EventFooter } from "@/components/EventFooter";
 import { cn } from "@/lib/utils";
 import { isAddressableKind } from "@/lib/nostr-kinds";
+import { getSemanticAuthor } from "@/lib/semantic-author";
 
 /**
  * Universal event properties and utilities shared across all kind renderers
@@ -173,9 +174,12 @@ export function EventMenu({ event }: { event: NostrEvent }) {
       };
     }
 
+    // Get semantic author (e.g., zapper for zaps, host for streams)
+    const recipientPubkey = getSemanticAuthor(event);
+
     // Open zap window with event context
     addWindow("zap", {
-      recipientPubkey: event.pubkey,
+      recipientPubkey,
       eventPointer,
     });
   };
diff --git a/src/lib/semantic-author.ts b/src/lib/semantic-author.ts
new file mode 100644
index 0000000..b28a2b3
--- /dev/null
+++ b/src/lib/semantic-author.ts
@@ -0,0 +1,41 @@
+/**
+ * Semantic Author Utilities
+ *
+ * Determines the "semantic author" of an event based on kind-specific logic.
+ * For most events, this is event.pubkey, but for certain event types the
+ * semantic author may be different (e.g., zapper for zaps, host for streams).
+ */
+
+import type { NostrEvent } from "@/types/nostr";
+import { getZapSender } from "applesauce-common/helpers/zap";
+import { getLiveHost } from "@/lib/live-activity";
+
+/**
+ * Get the semantic author of an event based on kind-specific logic
+ * Returns the pubkey that should be displayed as the "author" for UI purposes
+ *
+ * Examples:
+ * - Zaps (9735): Returns the zapper (P tag), not the lightning service pubkey
+ * - Live activities (30311): Returns the host (first p tag with "Host" role)
+ * - Regular events: Returns event.pubkey
+ *
+ * This function should be used when determining:
+ * - Who to display as the author in UI
+ * - Who to zap when zapping an event
+ * - Who the "owner" of the event is semantically
+ */
+export function getSemanticAuthor(event: NostrEvent): string {
+  switch (event.kind) {
+    case 9735: {
+      // Zap: show the zapper, not the lightning service pubkey
+      const zapSender = getZapSender(event);
+      return zapSender || event.pubkey;
+    }
+    case 30311: {
+      // Live activity: show the host
+      return getLiveHost(event);
+    }
+    default:
+      return event.pubkey;
+  }
+}