diff --git a/README.md b/README.md
index fc0402e..33c10b4 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,13 @@ A notepad-playable browser game that combines Tic Tac Toe's line-making goal wit
 docker compose up --build
 ```
 
-Then open `http://localhost:3000` in two browser windows. The first two connected players are paired automatically.
+Then open `http://localhost:8787` in two browser windows. The first two connected players are paired automatically.
+
+Set a different host port with:
+
+```powershell
+$env:APP_PORT=9090; docker compose up --build
+```
 
 Stop it with:
 
diff --git a/compose.yaml b/compose.yaml
index 3823519..b52dde3 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -8,5 +8,4 @@ services:
     environment:
       PORT: 3000
     ports:
-      - "3000:3000"
-
+      - "${APP_PORT:-8787}:3000"