diff --git a/endpoints-framework/src/main/java/com/google/api/server/spi/auth/EndpointsAuthenticator.java b/endpoints-framework/src/main/java/com/google/api/server/spi/auth/EndpointsAuthenticator.java
index ecdb7f7e..b5c56b48 100644
--- a/endpoints-framework/src/main/java/com/google/api/server/spi/auth/EndpointsAuthenticator.java
+++ b/endpoints-framework/src/main/java/com/google/api/server/spi/auth/EndpointsAuthenticator.java
@@ -38,7 +38,7 @@ public class EndpointsAuthenticator implements Authenticator {
 
   public EndpointsAuthenticator() {
     this.jwtAuthenticator = new GoogleJwtAuthenticator();
-    this.appEngineAuthenticator = new GoogleAppEngineAuthenticator();
+    this.appEngineAuthenticator = EnvUtil.isRunningOnAppEngine() ? new GoogleAppEngineAuthenticator() : null;
     this.oauth2Authenticator = new GoogleOAuth2Authenticator();
   }