We can use **/rest/V1/customers**: http://devdocs.magento.com/swagger/#resource_customerAccountManagementV1

For example, payload:

    {
      "id": 0,
      "group_id": 0,
      "default_billing": "string",
      "default_shipping": "string",
      "confirmation": "string",
      "created_at": "string",
      "updated_at": "string",
      "created_in": "string",
      "dob": "string",
      "email": "string",
      "firstname": "string",
      "lastname": "string",
      "middlename": "string",
      "prefix": "string",
      "suffix": "string",
      "gender": 0,
      "store_id": 0,
      "taxvat": "string",
      "website_id": 0,
      "addresses": [
        {
          "id": 0,
          "customer_id": 0,
          "region": {
            "region_code": "string",
            "region": "string",
            "region_id": 0,
            "extension_attributes": {}
          },
          "region_id": 0,
          "country_id": "string",
          "street": [
            "string"
          ],
          "company": "string",
          "telephone": "string",
          "fax": "string",
          "postcode": "string",
          "city": "string",
          "firstname": "string",
          "lastname": "string",
          "middlename": "string",
          "prefix": "string",
          "suffix": "string",
          "vat_id": "string",
          "default_shipping": true,
          "default_billing": true,
          "extension_attributes": {},
          "custom_attributes": [
            {
              "attribute_code": "string",
              "value": "string"
            }
          ]
        }
      ],