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validation_error

HTTP Status: 422 Unprocessable Entity

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Example response

{
  "error": {
    "code": "validation_error",
    "message": "Invalid request body: vat_numbers must contain between 1 and 50 items",
    "docs_url": "https://docs.vatly.dev/errors/validation_error"
  },
  "meta": {
    "request_id": "550e8400-e29b-41d4-a716-446655440000"
  }
}

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What happened?

The request body failed schema validation. This applies to endpoints that accept a JSON body, such as the batch validation endpoint. Common causes:
  • vat_numbers array is empty or contains more than 50 items
  • vat_numbers is not an array of strings
  • Required fields are missing from the request body
  • Extra fields with incorrect types were provided

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How to fix

  1. Check the message field: It describes exactly which validation rule failed
  2. Review the request body schema: See Batch Validation for the expected shape
  3. Ensure correct types: vat_numbers must be an array of strings, cache must be a boolean
# Correct
curl -X POST https://api.vatly.dev/v1/validate/batch \
  -H "Authorization: Bearer vtly_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"vat_numbers": ["NL123456789B01", "DE987654321"]}'

# Wrong - empty array
curl -X POST https://api.vatly.dev/v1/validate/batch \
  -H "Authorization: Bearer vtly_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"vat_numbers": []}'

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Common mistakes

  • Sending an empty array: vat_numbers must contain at least 1 item
  • Exceeding 50 items: Split large batches into multiple requests of 50 or fewer
  • Wrong Content-Type: Make sure you set Content-Type: application/json
  • Confusing with invalid_vat_format: validation_error is about the request structure; invalid_vat_format is about individual VAT number formats