diff --git a/src/core/create_manifests.ts b/src/core/create_manifests.ts
index 1e1a09a..a71ae52 100644
--- a/src/core/create_manifests.ts
+++ b/src/core/create_manifests.ts
@@ -127,9 +127,11 @@ function generate_client(
 
 		footer = `
 
-			import(${stringify(sapper_dev_client)}).then(client => {
-				client.connect(${dev_port});
-			});`.replace(/^\t{3}/gm, '');
+			if (typeof window !== 'undefined') {
+				import(${stringify(sapper_dev_client)}).then(client => {
+					client.connect(${dev_port});
+				});
+			}`.replace(/^\t{3}/gm, '');
 	}
 
 	return `// This file is generated by Sapper — do not edit it!\n` + template