diff --git a/.circleci/config.yml b/.circleci/config.yml
index dde28ea9083..2c407f7772f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -169,7 +169,7 @@ jobs:
           command: |
             # See https://circleci.com/docs/2.0/env-vars/#setting-an-environment-variable-in-a-shell-command
             TAG=$CIRCLE_SHA1 docker-compose -f ./docker/compose/docker-compose.yml up -d
-            yarn workspace @mui/toolpad-app waitForApp
+            yarn workspace @mui/toolpad-app waitForApp --url=http://172.17.0.1:3000/
             docker run -it --rm \
               --ipc=host \
               -v "$CIRCLE_WORKING_DIRECTORY:/tests" \
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 5e295e939ad..4facd4e09ee 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -35,6 +35,9 @@ If you would like to hack on MUI Toolpad or want to run the latest version, you
 
    ```sh
    TOOLPAD_DATABASE_URL=postgres://postgres:postgres@localhost:5432/postgres
+   # For a custom port:
+   # PORT=3004
+   # EXTERNAL_URL=http://localhost:3004/
    ```
 
 1. Now you can run the MUI Toolpad dev command to start the application
diff --git a/docker/compose/docker-compose.yml b/docker/compose/docker-compose.yml
index 6ad208d8b64..85ba4e10f81 100644
--- a/docker/compose/docker-compose.yml
+++ b/docker/compose/docker-compose.yml
@@ -5,6 +5,8 @@ services:
     image: muicom/toolpad:${TAG:-latest}
     environment:
       - TOOLPAD_DATABASE_URL=postgresql://toolpad-app:secretpw@postgres:5432/postgres?connect_timeout=10
+      - PORT=3000
+      - EXTERNAL_URL=http://localhost:3000/
     ports:
       - '3000:3000'