Our organisation has an ios/android app and would like to receive donation thru the app. Developer requires details of REST webserver endpoint of our civicrm to receive & post contact/contribution data. We are using drupal and civi 5.13. How do I get started? any help would be much appreciated. Thanks
CiviCRM provides api for each entity. Each entity has its own parameter. You can use API explorer to find how params are build and need to send through rest api. The API explorer screen provides detailed information about using various method of using api to perform CRUD operation on CiviCRM.
While using rest api you will need to pass Site key (stored in civicrm.settings.php) and User contact's api key (You can either set this in civicrm_contact table or use API Key extension to set and see the api key) as part of authentication.