Web services
From MoodleDocs
Template:Moodle 2.0 Web services enable other systems to login to Moodle and perform operations.
Enabling web services
To use web services, the feature must be enabled on the site by checking the enablewebservices box in Site Administration > Advanced features.
For security reasons, web services should only be enabled if you intend to make use of it.
User Manual
Administrator
How to enable web services for ordinary users
How to enable web services for an external system
Development
Development:Creating a web service and a web service function