Field Mappings are passed to the third party API as the request body.

For each Missing field mapping returned in the Step prerequisites request in step 7:

Request:

    GET /v1.0/steps/{Step ID}/fieldmappings/{Field ID}
    Authorization Bearer 0000000000000000000000000000000000000000000000000000000000000000
    X-Cyclr-Account: 00000000-0000-0000-0000-000000000000

Response:

    {
        "Field": {
            "Id": 283792,
            "Name": "Email",
            "Description": null,
            "IsOptional": false,
            "DataType": "Undefined",
            "TriggerName": null,
            "Values": [],
            "DisplayOrder": 1,
            "Triggers": []
        },
        "MappingType": "Ignore",
        "SourceFieldId": null,
        "SourceStepId": null,
        "TriggerValue": null,
        "TriggerValueDisplayName": null,
        "Value": null
    }

The IsOptional property indicates if a field mapping is optional or required before the Cycle can run.

There are multiple ways of setting a Field Mapping value.

Static Value Field Mapping
Field Mapping with Step Data
Value List Mapping