diff --git a/app/README.md b/app/README.md
index 9a43f94dd55efc2d29e8fa632eb22a3d8e49de2c..6ef67bb91748359cfcffb0d24ad8d74cd6652241 100644
--- a/app/README.md
+++ b/app/README.md
@@ -66,3 +66,14 @@ To build the project, run `npm run build`
 1. Run `npm run build` in directory `app` so that the static files are generated in subdirectory `dist`.
 
 2. Copy `dist` to a web server (e.g. Nginx) and let it serve.
+
+
+### Custom environmental variables
+
+If you want to modify the `NODE_ENV` or `API_URL` variables of the app, you can easily modify them by calling the `npm run dev` and `npm run prod` scripts respectively.
+
+Example
+
+```
+npm run dev -- --env.NODE_ENV=foobar --env.API_URL=http://localhost:1234
+```
diff --git a/app/package.json b/app/package.json
index 7e6a6da824bbed4e5754328f8bd0cb0124c7c158..337ff43682c39e0d4d854d25e2070d9f7743b0f4 100644
--- a/app/package.json
+++ b/app/package.json
@@ -5,6 +5,7 @@
   "main": "index.js",
   "scripts": {
     "build": "webpack --mode production --env.NODE_ENV=production --env.API_URL=https://dev.fevermap.net",
+    "prod": "webpack --mode production",
     "dev": "webpack --mode development"
   },
   "author": "",