by Mayank Tyagi.
Hi Ghislain,
Yes, it is possible to access Moodle's APIs like Web Services as a teacher. For web services just create a token for the user for which you want to create access capability. you can create a token from Site Administration > Plugins > Webservices > Manage Tokens or hit http://example.com/admin/settings.php?section=webservicetokens.
Regards,
Mayank Tyagi