diff --git a/homeassistant/components/alexa/__init__.py b/homeassistant/components/alexa/__init__.py
index 219553b3563..2a9637772b1 100644
--- a/homeassistant/components/alexa/__init__.py
+++ b/homeassistant/components/alexa/__init__.py
@@ -36,6 +36,15 @@ CONF_FLASH_BRIEFINGS = "flash_briefings"
 CONF_SMART_HOME = "smart_home"
 DEFAULT_LOCALE = "en-US"
 
+# Alexa Smart Home API send events gateway endpoints
+# https://developer.amazon.com/en-US/docs/alexa/smarthome/send-events.html#endpoints
+VALID_ENDPOINTS = [
+    "https://api.amazonalexa.com/v3/events",
+    "https://api.eu.amazonalexa.com/v3/events",
+    "https://api.fe.amazonalexa.com/v3/events",
+]
+
+
 ALEXA_ENTITY_SCHEMA = vol.Schema(
     {
         vol.Optional(CONF_DESCRIPTION): cv.string,
@@ -46,7 +55,7 @@ ALEXA_ENTITY_SCHEMA = vol.Schema(
 
 SMART_HOME_SCHEMA = vol.Schema(
     {
-        vol.Optional(CONF_ENDPOINT): cv.string,
+        vol.Optional(CONF_ENDPOINT): vol.All(vol.Lower, vol.In(VALID_ENDPOINTS)),
         vol.Optional(CONF_CLIENT_ID): cv.string,
         vol.Optional(CONF_CLIENT_SECRET): cv.string,
         vol.Optional(CONF_LOCALE, default=DEFAULT_LOCALE): vol.In(