diff --git a/packages/backend/src/config/load.ts b/packages/backend/src/config/load.ts
index 9b8ee5edbb..fa98789554 100644
--- a/packages/backend/src/config/load.ts
+++ b/packages/backend/src/config/load.ts
@@ -55,6 +55,8 @@ export default function load() {
 	mixin.clientEntry = clientManifest["src/init.ts"];
 
 	if (!config.redis.prefix) config.redis.prefix = mixin.host;
+	if (config.cacheServer && !config.cacheServer.prefix)
+		config.cacheServer.prefix = mixin.host;
 
 	return Object.assign(config, mixin);
 }
diff --git a/packages/backend/src/config/types.ts b/packages/backend/src/config/types.ts
index 43168662c4..7789c26e07 100644
--- a/packages/backend/src/config/types.ts
+++ b/packages/backend/src/config/types.ts
@@ -26,7 +26,7 @@ export type Source = {
 		user?: string;
 		tls?: { [y: string]: string };
 	};
-	cacheServer: {
+	cacheServer?: {
 		host: string;
 		port: number;
 		family?: number;