For a PTZ camera, are Continuous and Relative motion supported by the REST API?

We are integrating using the REST api, which is working well, but I am unable to find any reference to continuous or relative motion anywhere. Does this functionality exist within the REST API?

No.

The REST API only have:

GetPtzAbsolutePosition - Get absolute position

SetPtzAbsolutePosition - Set absolute position

Ref. https://doc.developer.milestonesys.com/mipvmsapi/api/config-rest/v1/#tag/DeviceConfig/operation/postTaskForCameras

Thank you for clarifying.

Is continuous or relative motion available via any API?

The MIP SDK -

https://doc.developer.milestonesys.com/mipsdk/index.html?base=samples%2FComponentSamples%2FPTZandPresets%2FREADME.html&tree=tree_2.html

Underneath the SDK uses the RecorderCommandService (SOAP) -

https://doc.developer.milestonesys.com/mipsdk/index.html?base=RecorderSOAPhelp%2Fclass_recorder_command_service.html&tree=tree_3.html