diff --git a/docs/en/docs/guides/development/environment-variables.mdx b/docs/en/docs/guides/development/environment-variables.mdx
index 0dfcf71..a6edc00 100644
--- a/docs/en/docs/guides/development/environment-variables.mdx
+++ b/docs/en/docs/guides/development/environment-variables.mdx
@@ -24,6 +24,7 @@ The following file names are supported:
 
 1. Create a new file using one of the supported file names at the same folder level as your `manifest.json` file.
 2. In your extension code, add the Node.js pattern of `process.env.YOUR_VARIABLE_NAME`.
+3. Make sure to prefix all your environment variables with `EXTENSION_PUBLIC_`.
 
 > TIP: Environment variables are not supported in the `manifest.json` file.