diff --git a/src/argv.ts b/src/argv.ts
index da22e5fdfc..211b42a529 100644
--- a/src/argv.ts
+++ b/src/argv.ts
@@ -6,6 +6,7 @@ program
 	.option('--no-daemons', 'Disable daemon processes (for debbuging)')
 	.option('--disable-clustering', 'Disable clustering')
 	.option('--quiet', 'Suppress all logs')
+	.option('--slow', 'Delay all requests (for debbuging)')
 	.parse(process.argv);
 
 export { program };
diff --git a/src/server/index.ts b/src/server/index.ts
index be0a6f5c77..26fa06d111 100644
--- a/src/server/index.ts
+++ b/src/server/index.ts
@@ -13,7 +13,7 @@ import * as mount from 'koa-mount';
 import * as compress from 'koa-compress';
 import * as koaLogger from 'koa-logger';
 import * as requestStats from 'request-stats';
-//import * as slow from 'koa-slow';
+import * as slow from 'koa-slow';
 
 import activityPub from './activitypub';
 import webFinger from './webfinger';
@@ -23,6 +23,7 @@ import apiServer from './api';
 import { sum } from '../prelude/array';
 import User from '../models/user';
 import Logger from '../misc/logger';
+import { program } from '../argv';
 
 export const serverLogger = new Logger('server', 'gray');
 
@@ -37,9 +38,11 @@ if (!['production', 'test'].includes(process.env.NODE_ENV)) {
 	}));
 
 	// Delay
-	//app.use(slow({
-	//	delay: 1000
-	//}));
+	if (program.slow) {
+		app.use(slow({
+			delay: 3000
+		}));
+	}
 }
 
 // Compress response