diff --git a/fixed-price-subscriptions/server/go/server.go b/fixed-price-subscriptions/server/go/server.go
index b5fc9ee2..3485e314 100644
--- a/fixed-price-subscriptions/server/go/server.go
+++ b/fixed-price-subscriptions/server/go/server.go
@@ -36,7 +36,7 @@ func main() {
 	http.HandleFunc("/retrieve-upcoming-invoice", handleRetrieveUpcomingInvoice)
 	http.HandleFunc("/stripe-webhook", handleWebhook)
 
-	addr := "localhost:4242"
+	addr := "0.0.0.0:4242"
 	log.Printf("Listening on %s ...", addr)
 	log.Fatal(http.ListenAndServe(addr, nil))
 }
diff --git a/fixed-price-subscriptions/server/php/composer.json b/fixed-price-subscriptions/server/php/composer.json
index 7f69324e..085334de 100644
--- a/fixed-price-subscriptions/server/php/composer.json
+++ b/fixed-price-subscriptions/server/php/composer.json
@@ -9,6 +9,6 @@
     "monolog/monolog": "^1.17"
   },
   "scripts": {
-    "start": "php -S localhost:4242 index.php"
+    "start": "php -S 0.0.0.0:4242 index.php"
   }
 }
diff --git a/per-seat-subscriptions/server/go/server.go b/per-seat-subscriptions/server/go/server.go
index d21a6e21..6e55cd7b 100644
--- a/per-seat-subscriptions/server/go/server.go
+++ b/per-seat-subscriptions/server/go/server.go
@@ -49,7 +49,7 @@ func main() {
 	http.HandleFunc("/cancel-subscription", handleCancelSubscription)
 	http.HandleFunc("/stripe-webhook", handleWebhook)
 
-	addr := "localhost:4242"
+	addr := "0.0.0.0:4242"
 	log.Printf("Listening on %s ...", addr)
 	log.Fatal(http.ListenAndServe(addr, nil))
 }
diff --git a/per-seat-subscriptions/server/php/composer.json b/per-seat-subscriptions/server/php/composer.json
index 3f44ca60..11b18b66 100644
--- a/per-seat-subscriptions/server/php/composer.json
+++ b/per-seat-subscriptions/server/php/composer.json
@@ -9,6 +9,6 @@
     "monolog/monolog": "^1.17"
   },
   "scripts": {
-    "start": "php -S localhost:4242 index.php"
+    "start": "php -S 0.0.0.0:4242 index.php"
   }
 }
diff --git a/usage-based-subscriptions/server/go/server.go b/usage-based-subscriptions/server/go/server.go
index 81157459..b8a788c8 100644
--- a/usage-based-subscriptions/server/go/server.go
+++ b/usage-based-subscriptions/server/go/server.go
@@ -36,7 +36,7 @@ func main() {
 	http.HandleFunc("/retrieve-upcoming-invoice", handleRetrieveUpcomingInvoice)
 	http.HandleFunc("/stripe-webhook", handleWebhook)
 
-	addr := "localhost:4242"
+	addr := "0.0.0.0:4242"
 	log.Printf("Listening on %s ...", addr)
 	log.Fatal(http.ListenAndServe(addr, nil))
 }
diff --git a/usage-based-subscriptions/server/php/composer.json b/usage-based-subscriptions/server/php/composer.json
index 9600fe5b..26c3d5b9 100644
--- a/usage-based-subscriptions/server/php/composer.json
+++ b/usage-based-subscriptions/server/php/composer.json
@@ -10,6 +10,6 @@
     "ramsey/uuid": "^4.0"
   },
   "scripts": {
-    "start": "php -S localhost:4242 index.php"
+    "start": "php -S 0.0.0.0:4242 index.php"
   }
 }