The APIs return AusTender contract notice (CN) data in the OCDS-compliant schema, and includes data published from 1 January 2013.
There are various Contract Notice API calls available:
Search by Contract Notice Published Date
Search by Contract Notice Start Date
Search by Contract Notice End Date
Search by Contract Notice Latest Modified Date
Detailed documentation for the API can be found on https://app.swaggerhub.com/apis/austender/ocds-api/1.1#/