diff --git a/README.md b/README.md
index 120ecc0..d0dc22c 100644
--- a/README.md
+++ b/README.md
@@ -58,8 +58,9 @@ $ webpack-serve --help
     --no-hot            Instruct the client not to apply Hot Module Replacement patches
     --no-reload         Instruct middleware {italic not} to reload the page for build errors
     --open              Instruct the app to open in the default browser
-    --open-app          The name of the app to open the app within, or an array
+    --open-app          The name of the app to open the app within, or a JSON array
                         containing the app name and arguments for the app
+                        (see https://github.com/sindresorhus/opn#app)
     --open-path         The path with the app a browser should open to
     --port              The port the app should listen on
     --version           Display the webpack-serve version
@@ -420,4 +421,4 @@ We welcome your contributions! Please have a read of
 
 [dev-ware]: https://github.com/webpack/webpack-dev-middleware#options
 [hot-client]: https://github.com/webpack-contrib/webpack-hot-client#options
-[https-opts]: https://nodejs.org/api/tls.html#tls_tls_createsecurecontext_options
\ No newline at end of file
+[https-opts]: https://nodejs.org/api/tls.html#tls_tls_createsecurecontext_options