curl --request POST \
  --url https://api.slash.com/customer \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "name": "<string>",
  "email": "<string>",
  "phone": "<string>",
  "customMetadata": {}
}
'

{
  "customer": {
    "id": "<string>",
    "name": "<string>",
    "email": "<string>",
    "status": "active",
    "phone": "<string>",
    "address": {},
    "customMetadata": {}
  }
}