diff --git a/src/server.ts b/src/server.ts
index 9c38fad..6f6b495 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -520,20 +520,21 @@ const server = Bun.serve<SessionData>({
             return;
           }
 
-          // Write to terminal emulator (handles all ANSI sequences)
-          termSession.terminal.write(msg.data);
-
           // Store raw ANSI in database
           appendOutput(sessionId, msg.data);
 
-          // Serialize current terminal state as HTML
-          const html = serializeAsHTML(termSession);
+          // Write to terminal emulator (handles all ANSI sequences)
+          // Use callback to wait for write completion before serializing
+          termSession.terminal.write(msg.data, () => {
+            // Serialize current terminal state as HTML
+            const html = serializeAsHTML(termSession);
 
-          // Broadcast to dashboards
-          broadcastSSE({
-            type: "output",
-            session_id: sessionId,
-            data: html,
+            // Broadcast to dashboards
+            broadcastSSE({
+              type: "output",
+              session_id: sessionId,
+              data: html,
+            });
           });
 
           return;