diff --git a/.env.development b/.env.development
index af56fe2..4d321d2 100644
--- a/.env.development
+++ b/.env.development
@@ -1,4 +1,3 @@
-PUBLIC_URL=http://localhost:3000
 API_URL=http://localhost:8080
 
 REACT_APP_WEBSITE_NAME="RetroPilot Connect - Development"
diff --git a/README.md b/README.md
index eadbcbc..f3c5c8c 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,12 @@ React client for Retropilot
 
 Ties into https://github.com/retropilot/retropilot-server/ to provide a react frontend
 
+## Environment Variables
+
+The app configuration (see `src/config.js`) is loaded from environment variables. A different
+different environment can be configured for development (`npm run start`), testing (`npm test`) and
+production (`npm run build`).
+
 To override the environment variables, create a `.env.local` file. You can also override the
-variables for development, testing and production independently (`.env.development`,
-`.env.test.local` and `.env.production.local` files).
+variables for development, testing and production independently (`.env.development`, `.env.test.local` and `.env.production.local`
+files). Set the `API_URL` to the address of the RetroPilot server, such as `http://localhost:8080` or `https://api.retropilot.local`.