const options = {
  method: 'GET',
  headers: {'x-organization-id': '<x-organization-id>', 'x-api-key': '<api-key>'}
};

fetch('https://api.dcycle.io/v2/imports/templates/{template_id}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "template_id": "<string>",
  "columns": [
    {
      "key": "<string>",
      "label": "<string>",
      "type": "<string>",
      "required": false,
      "aliases": [
        "<string>"
      ],
      "options": [
        "<string>"
      ],
      "options_source": "countries",
      "default": "<unknown>",
      "validations": [
        {}
      ]
    }
  ]
}