Which particular APIs are you interested in? There's a pretty extensive list of webservice functions already available (which can be accessed via REST, SOAP or XMLRPC): https://docs.moodle.org/dev/Web_service_API_functions
Which particular APIs are you interested in? There's a pretty extensive list of webservice functions already available (which can be accessed via REST, SOAP or XMLRPC): https://docs.moodle.org/dev/Web_service_API_functions