const options = {
  method: 'POST',
  headers: {
    'X-Spree-Seller-Id': '<x-spree-seller-id>',
    Authorization: 'Bearer <token>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    name: '<string>',
    admin_name: '<string>',
    code: '<string>',
    delivery_profile_id: '<string>',
    delivery_zone_id: '<string>',
    storefront_visible: true,
    tracking_url: '<string>',
    estimated_transit_business_days_min: 123,
    estimated_transit_business_days_max: 123,
    calculator_type: '<string>',
    calculator_preferences: {},
    rules: [{type: '<string>', preferences: {}}]
  })
};

fetch('http://{defaultHost}/api/v3/seller/delivery_methods', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

curl --request POST \
  --url http://{defaultHost}/api/v3/seller/delivery_methods \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'X-Spree-Seller-Id: <x-spree-seller-id>' \
  --data '
{
  "name": "<string>",
  "admin_name": "<string>",
  "code": "<string>",
  "delivery_profile_id": "<string>",
  "delivery_zone_id": "<string>",
  "storefront_visible": true,
  "tracking_url": "<string>",
  "estimated_transit_business_days_min": 123,
  "estimated_transit_business_days_max": 123,
  "calculator_type": "<string>",
  "calculator_preferences": {},
  "rules": [
    {
      "type": "<string>",
      "preferences": {}
    }
  ]
}
'

{
  "id": "dm_EfhxLZ9ck8",
  "name": "Next day",
  "code": null,
  "estimated_transit_business_days_min": null,
  "estimated_transit_business_days_max": null,
  "digital": false,
  "pickup": false,
  "pickup_point": false,
  "admin_name": null,
  "storefront_visible": true,
  "tracking_url": null,
  "created_at": "2026-01-15T12:00:00.000Z",
  "updated_at": "2026-01-15T12:00:00.000Z",
  "rules": [],
  "editable": true,
  "delivery_profile_id": "fp_gbHJdmfrXB",
  "delivery_zone_id": null,
  "calculator_type": "flat_rate",
  "calculator_preferences": {
    "amounts": {},
    "amount": "9.99",
    "currency": "USD"
  }
}

{
  "error": {
    "code": "validation_error",
    "message": "Name can't be blank",
    "details": {
      "name": [
        "can't be blank"
      ]
    }
  }
}