The latest update of the API added rotating proxy support to it. It is available by default to all request made by the API.
You can still add your own proxies, using the proxy_url API parameter, available in all API nodes (excepting Tor node, which uses Onion/Tor proxies).
You can also disable the usage of the rotating proxies, by setting the proxy_url API parameter to the value: disabled.
Happy scraping!