diff --git a/README.md b/README.md
index fb6cc988..0b9d6c2b 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,17 @@ See one of the following guides:
 
 [Production installation](docs/deployment.md)
 
+Setting the desired Symfony application environment
+===================================================
+There are 2 ways you can influence the desired Symfony application environment.
+
+1. Set the `app_env` parameter in `config/openconext/parameters.yaml` to `dev`, `test` or `prod`
+2. Override the `app_env` param by providing an environment variable named `APP_ENV`
+
+- The default value for the application environment will be `prod`
+- Do not try to use a .env file to override the `app_env` param. That file will not be evaluated by Symfony as we decided not use the DotEnv component.
+
+
 Tests and metrics
 ======================
 
diff --git a/config/bootstrap.php b/config/bootstrap.php
index e0c74aeb..9c7d3a6c 100644
--- a/config/bootstrap.php
+++ b/config/bootstrap.php
@@ -21,4 +21,9 @@
 $_SERVER['APP_DEBUG'] = $parameters['app_debug'];
 $_SERVER['APP_SECRET'] = $parameters['app_secret'];
 
+// Allow the application environment (dev/test/prod) to change via the APP_ENV environment variable.
+if (array_key_exists('APP_ENV', $_ENV)) {
+    $_SERVER['APP_ENV'] = $_ENV['APP_ENV'];
+}
+
 filter_var($_SERVER['APP_DEBUG'], FILTER_VALIDATE_BOOLEAN) ? '1' : '0';