To retrieve the last-seen validation result, use the following URL and the GET method:

{service_url}/bulk/api/v3/tax_numbers/validate?last-seen-id={last_seen_id}

Here, {service_url} is the URL of the sandbox or production environment, and {last_seen_id} is the items.id value returned from the Poll Results request.

Restrictions

This request returns only processed validations. Each subsequent request may return additional results as processing continues, until the entire batch is complete.

Details

Endpoint	Method
`/bulk/api/v3/tax_numbers/validate?{last-seen-id}`	GET

Input parameters

Parameter	Detail
`last-seen-id`	The `items.id` field value returned from the Poll Results response.

Request example

https://tax-id-validator-bulk-api.sandbox.marketplace.taxamo.com/bulk/api/v3/tax_numbers/validate?last-seen-id=CMGpMhACMAA=

Response example

{
    "items": [
        {
            "status": "processed",
            "request_id": "ANKpMhAXMAA=",
            "id": "CMGpMhACMAA=",
            "output": {
                "buyer_tax_number_valid": false,
                "buyer_tax_number_format_valid": false,
                "buyer_tax_number_validation_info": "tax-number-syntax-invalid"
            }
        },
        {
            "status": "processed",
            "request_id": "ANKpMhAYMAA=",
            "id": "CMGpMhAFMAA=", 
            "output": {
                "buyer_tax_number_valid": false,
                "buyer_tax_number_format_valid": true,
                "buyer_tax_number_validation_info": "tax-number-invalid-according-to-external-service",
                "buyer_tax_number_normalized": "111111111",
                "buyer_tax_number_service_cache_used": true,
                "buyer_tax_number_service_cache_timestamp": "2025-08-20T15:07:34Z",
                "tax_number_service": "tax.service.gov.uk.api"
            }
        }
    ]
}