[[duilioisola]]

Por lo que leí en la web que envías están publicados los endpoints en formato YAML para poder ser leido en la web https://editor.swagger.io/
El fichero YAML indica las "paths" que serían los endpoints y los parámetros que puedes utilizar.
Descarge el fichero y luego en la web que mencionan ves al menú "File" -> "Import File" y seleccionas el fichero.

Parece que hay tres endpoints
/check-vat-number
Ejemplo con CURL

curl -X 'POST' \
  'https://editor.swagger.io/check-vat-number' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
  "countryCode": "ES",
  "vatNumber": "X3245299E",
  "requesterMemberStateCode": "ES",
  "requesterNumber": "1",
  "traderName": "TEST",
  "traderStreet": "STR",
  "traderPostalCode": "08035",
  "traderCity": "Barcelona",
  "traderCompanyType": "eCommerce"
}'

/check-vat-test-service
/check-status

Contenido del fichero YAML

swagger: "2.0"
info:
  description: "This is the contract for Vies on-the-Web endpoints. 
  The checkVat service supports exact and approximate matching at the same time. 
  In order to retrieve the requestIdentifier, the information about requesterMemberStateCode and requesterNumber have to be provided."
  version: "1.0.0"
  title: "Vies on-the-Web Endpoint"
produces:
  - "application/json"
schemes:
  - "https"
paths:
  /check-vat-number:
    post:
      tags:
        - "public"
      summary: "Check a Vat Number for a specific country"
      operationId: "checkVatNumber"
      parameters:
        - name: "body"
          in: "body"
          description: "The request body"
          required: true
          schema:
            $ref: "#/definitions/CheckVatRequest"
      responses:
        "200":
          description: "Successful operation"
          schema:
            $ref: "#/definitions/CheckVatResponse"
        "400":
          description: "Bad Request"
          schema:
            $ref: "#/definitions/CommonResponse"
        "500":
          description: "Internal server error"
          schema:
            $ref: "#/definitions/CommonResponse"
  /check-vat-test-service:
    post:
      tags:
        - "public"
      summary: "Test the check vat service"
      operationId: "checkVatTestService"
      parameters:
        - name: "body"
          in: "body"
          description: "The request body"
          required: true
          schema:
            $ref: "#/definitions/CheckVatRequest"
      responses:
        "200":
          description: "Successful operation"
          schema:
            $ref: "#/definitions/CheckVatResponse"
        "400":
          description: "Bad Request"
          schema:
            $ref: "#/definitions/CommonResponse"
        "500":
          description: "Internal server error"
          schema:
            $ref: "#/definitions/CommonResponse"
  /check-status:
    get:
      tags:
        - "public"
      summary: "Check the status of each member states"
      operationId: "checkStatus"
      responses:
        "200":
          description: "Successful operation"
          schema:
            $ref: "#/definitions/StatusInformationResponse"
        "400":
          description: "Bad Request"
          schema:
            $ref: "#/definitions/CommonResponse"
        "500":
          description: "Internal server error"
          schema:
            $ref: "#/definitions/CommonResponse"
definitions:
  Match:
    type: "string"
    enum:
      - "VALID"
      - "INVALID"
      - "NOT_PROCESSED"
  CheckVatRequest:
    type: "object"
    properties:
      countryCode:
        type: "string"
      vatNumber:
        type: "string"
      requesterMemberStateCode:
        type: "string"
      requesterNumber:
        type: "string"
      traderName:
        type: "string"
      traderStreet:
        type: "string"
      traderPostalCode:
        type: "string"
      traderCity:
        type: "string"
      traderCompanyType:
        type: "string"
  CheckVatResponse:
    type: "object"
    properties:
      countryCode:
        type: "string"
      vatNumber:
        type: "string"
      requestDate:
        type: "string"
        format: "date-time"
      valid:
        type: "boolean"
      requestIdentifier:
        type: "string"
      name:
        type: "string"
      address:
        type: "string"
      traderName:
        type: "string"
      traderStreet:
        type: "string"
      traderPostalCode:
        type: "string"
      traderCity:
        type: "string"
      traderCompanyType:
        type: "string"
      traderNameMatch:
        $ref: "#/definitions/Match"
      traderStreetMatch:
        $ref: "#/definitions/Match"
      traderPostalCodeMatch:
        $ref: "#/definitions/Match"
      traderCityMatch:
        $ref: "#/definitions/Match"
      traderCompanyTypeMatch:
        $ref: "#/definitions/Match"
  CountryStatus:
    type: "object"
    properties:
      countryCode:
        type: "string"
      availability:
        type: "string"
        enum:
          - "Available"
          - "Unavailable"
          - "Monitoring Disabled"
  StatusInformationResponse:
    type: "object"
    properties:
      vow:
        type: "object"
        properties:
          available:
            type: "boolean"
      countries:
        type: "array"
        items:
          $ref: "#/definitions/CountryStatus"
  CommonResponse:
    type: "object"
    properties:
      actionSucceed:
        type: "boolean"
        description: "Indicate if the action succeed or not"
      errorWrappers:
        $ref: "#/definitions/ErrorWrappers"
  ErrorWrappers:
    type: "array"
    description: "Indicate the cause of the error when actionSucceed is false."
    items:
      $ref: "#/definitions/ErrorWrapper"
  ErrorWrapper:
    type: "object"
    description: "Define information about an error"
    properties:
      error:
        type: "string"
        description: "The error code"
      message:
        type: "string"