​

missing_parameter

​

Example response

{
  "error": {
    "code": "missing_parameter",
    "message": "Query parameter 'vat_number' is required",
    "docs_url": "https://docs.avatcado.com/errors/missing_parameter"
  },
  "meta": {
    "request_id": "550e8400-e29b-41d4-a716-446655440000"
  }
}

​

What happened?

• The vat_number parameter is completely absent from the URL
• The parameter name is misspelled (e.g., vatNumber instead of vat_number)
• The request body was sent instead of query parameters

​

How to fix

1. Add the vat_number query parameter to your request URL
2. Make sure you’re using snake_case: vat_number, not vatNumber or vatnumber
3. Pass VAT numbers as query parameters, not in the request body

# Correct
curl -H "Authorization: Bearer avat_live_your_api_key" \
  "https://api.avatcado.com/v1/validate?vat_number=NL123456789B01"

# Wrong - missing parameter
curl -H "Authorization: Bearer avat_live_your_api_key" \
  "https://api.avatcado.com/v1/validate"

​

Common mistakes

• Using vatNumber or vat-number instead of vat_number
• Sending a POST request with a JSON body instead of a GET with query params
• URL-encoding the ? character, preventing the parameter from being parsed

​

Catching this error with the SDKs

import Avatcado, { ValidationError } from '@avatcado/node';

const avatcado = new Avatcado('avat_live_your_api_key');
const { data, error } = await avatcado.vat.validate({ vatNumber: '...' });

if (error instanceof ValidationError) {
  console.log(error.message);
  console.log(error.details); // Array<{ field, message }> | null
}

from avatcado import Avatcado, ValidationError

avatcado = Avatcado("avat_live_your_api_key")

try:
    result = avatcado.vat.validate("...")
except ValidationError as e:
    print(e.message)
    print(e.details)  # list of dicts or None

​

Related errors

• invalid_vat_format - Parameter present but format is wrong