diff --git a/docker-compose.dev.yml b/docker-compose.dev.yml
index ad36e6af9..144a50985 100644
--- a/docker-compose.dev.yml
+++ b/docker-compose.dev.yml
@@ -9,7 +9,7 @@ services:
     volumes:
       - .:/app
     ports:
-      - "8000:8000"
+      - "127.0.0.1:8000:8000"
     command: python main.py --reload --host 0.0.0.0 --port 8000
     environment:
       PYTHONPATH: /app/
@@ -21,7 +21,7 @@ services:
     volumes:
       - ./frontend/:/app/frontend/
     ports:
-      - "3000:3000"
+      - "127.0.0.1:3000:3000"
     command: ash -c 'yarn install && yarn start'
     environment:
       TZ: Asia/Tokyo
diff --git a/docker-compose.yml b/docker-compose.yml
index 9f8c70d86..f83d298b6 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -11,7 +11,7 @@ services:
       - ../optinist-docker-volumes/logs/:/app/logs
       - ../optinist-docker-volumes/studio_data/:/app/studio_data
     ports:
-      - "8000:8000"
+      - "127.0.0.1:8000:8000"
     command: python main.py --host 0.0.0.0 --port 8000
     environment:
       PYTHONPATH: /app/
diff --git a/frontend/.env.example b/frontend/.env.example
index 5f5a5b922..da85c5f13 100644
--- a/frontend/.env.example
+++ b/frontend/.env.example
@@ -1,3 +1,10 @@
+# app config
+# PORT=3000 (default: 3000)
+
+# server endpoint
 REACT_APP_SERVER_HOST=localhost
 REACT_APP_SERVER_PORT=8000
+REACT_APP_SERVER_PROTO=http
+
+# running mode (true: standalone mode, false: multi-user mode)
 REACT_APP_IS_STANDALONE=true
diff --git a/frontend/src/const/API.ts b/frontend/src/const/API.ts
index 935ce3ae6..029a7fa58 100644
--- a/frontend/src/const/API.ts
+++ b/frontend/src/const/API.ts
@@ -1,5 +1,6 @@
 const HOST = process.env.REACT_APP_SERVER_HOST ?? "localhost"
 const PORT = process.env.REACT_APP_SERVER_PORT ?? 8000
+const PROTO = process.env.REACT_APP_SERVER_PROTO ?? "http"
 
-export const BASE_URL = `http://${HOST}:${PORT}`
-export const WS_BASE_URL = `ws://${HOST}:${PORT}`
+export const BASE_URL =
+  PORT == null ? `${PROTO}://${HOST}` : `${PROTO}://${HOST}:${PORT}`