curl --request POST \
  --url https://eu1.api.matillion.com/dpc/v1/projects/{projectId}/variables \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "description": "<string>",
  "name": "<string>",
  "supportsDoubleResolution": true,
  "value": "<unknown>"
}
'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "name": "<string>",
  "value": "<unknown>"
}