diff --git a/packages/react-cosmos-renderer/src/rendererConnect/createWebSocketsConnect.ts b/packages/react-cosmos-renderer/src/rendererConnect/createWebSocketsConnect.ts
index fbcf6d92f9..131b582fe4 100644
--- a/packages/react-cosmos-renderer/src/rendererConnect/createWebSocketsConnect.ts
+++ b/packages/react-cosmos-renderer/src/rendererConnect/createWebSocketsConnect.ts
@@ -1,10 +1,17 @@
 import {
   RendererConnect,
   RendererRequest,
+  RendererResponse,
   SocketMessage,
   rendererSocketMessage,
 } from 'react-cosmos-core';
 
+declare global {
+  interface Window {
+    cosmosRendererResponse?: (msg: RendererResponse) => void;
+  }
+}
+
 export function createWebSocketsConnect(url: string): RendererConnect {
   let pendingMessages: SocketMessage[] = [];
 
@@ -24,6 +31,11 @@ export function createWebSocketsConnect(url: string): RendererConnect {
       } else {
         pendingMessages.push(socketMessage);
       }
+
+      // Allow headless browsers to capture renderer responses
+      if (window.cosmosRendererResponse) {
+        window.cosmosRendererResponse(rendererResponse);
+      }
     },
 
     onMessage(onMessage) {