Create a Tax Rate

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    tax_rate: {
      amount: 0.05,
      tax_category_id: '1',
      calculator_attributes: {type: 'Spree::Calculator::FlatRate', preferences: {amount: 0, currency: 'USD'}},
      zone_id: '2',
      included_in_price: true,
      name: 'California',
      show_rate_in_label: false
    }
  })
};

fetch('http://{defaultHost}/api/v2/platform/tax_rates', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "data": {
    "id": "16",
    "type": "tax_rate",
    "attributes": {
      "amount": "0.1",
      "included_in_price": false,
      "created_at": "2022-11-08T19:35:44.601Z",
      "updated_at": "2022-11-08T19:35:44.601Z",
      "name": "TaxRate - 772641",
      "show_rate_in_label": true,
      "deleted_at": null,
      "public_metadata": {},
      "private_metadata": {}
    },
    "relationships": {
      "zone": {
        "data": null
      },
      "tax_category": {
        "data": {
          "id": "167",
          "type": "tax_category"
        }
      }
    }
  }
}