curl --request POST \
  --url https://api.embedreach.com/api/resources/customers/{externalId} \
  --header 'Content-Type: application/json' \
  --data '{
  "data": {
    "customerId": "<string>",
    "email": "<string>",
    "phone": "<string>",
    "firstName": "<string>",
    "lastName": "<string>",
    "emailOptOut": true,
    "smsOptOut": true,
    "customerDetailUrl": "<string>",
    "createdAt": "<string>"
  }
}'

{
  "success": true,
  "message": "<string>",
  "data": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "schema_definition_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "schemaDefinitionId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "platform_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "platformId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "business_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "businessId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "resource_external_id": "<string>",
    "resourceExternalId": "<string>",
    "created_at": "<string>",
    "createdAt": "<string>",
    "updated_at": "<string>",
    "updatedAt": "<string>",
    "data": {}
  }
}