REST API

REST API

I wish to use my Zoho Creator database to deliver data for a content management system (CMS) web site. So, I wish to use an API to get data from the database and I'm writing the web side of things using PHP (or similar). Apparently, there were speed issues with the REST API. So:

1) What API should I use for my CMS system?
2) How do I make API calls from PHP scripts (the documented API calls don't work)?
3) Have the speed issues with the REST API been sorted?