iDRAC9 Redfish API Guide:
For the latest iDRAC Redfish API guide, go to developer.dell.com. Under the Servers section, select iDRAC9 Redfish API.
To access any of the 4.xx, 5.xx, 6.xx, or 7.xx versions on developer.dell.com/apis, go to the latest API guide and select the version series.
For all the previous versions such as 3.00.00.00 or 3.40.40.40, go to dell.com/idracmanual.
iDRAC8 Redfish API Guide:
RESTful Server Configuration with iDRAC RESTful API white paper