If you are seeing performance issues with the HAPI calls, we recommend that you enable Cache Rendering for Performance on your page. Please note that this ONLY works for pages that are not personalized (meaning you aren't using customer attributes or pass in the customer_no) - this will be available in the future.
To enable this feature, go to the content page you want to enable this on, go to Settings and then enter the value in minutes. We recommend 120 minutes so it refreshes every 2 hours. Keep in mind the page will grab new data the next time someone accesses the page after the expiration time.
If you make a change to your page, upon saving we will generate a new cache.