To retrieve the most-recent bulk validation results, use the following URL and the GET method:

{service_url}/bulk/api/v3/tax_numbers/validate

Here, {service_url} is the URL of the sandbox or production environment.

Restrictions

The response supports up to 100 results per request.

Details

Endpoint	Method
`/bulk/api/v3/tax_numbers/validate`	GET

Output parameters

Field	Description
`items.status`	Returns the overall validation status for the tax number processing result.
`items.status.request_id`	Indicates the original request that submitted the tax number validation.
`items.status.id`	Indicates the specific validation result. This identifier can be used with the Poll Last Seen Result request to retrieve incremental updates.
`items.status.output.buyer_tax_number_valid`	Indicates whether the tax number is valid.
`items.status.output.buyer_tax_number_format_valid`	Indicates whether the tax number format and syntax are valid.
`items.status.output.buyer_tax_number_Validation_info`	Returns additional details about the validation outcome, such as syntax or verification errors (for example, `tax-number-syntax-invalid`).
`items.status.output.buyer_tax_number_normalized`	Returns the tax number in a standardized, normalized format.
`items.status.output.buyer_tax_service_cache_used`	Indicates whether a cached validation result was used instead of real-time validation.
`items.status.output.buyer_tax_service_cache_timestamp`	Returns the timestamp when the cached validation result was stored.
`tax_number_service`	Indicates the external service used to validate the tax number (for example, VIES).

The response also contains the same output parameters as any other Vertex Validator response.

Request example

https://tax-id-validator-bulk-api.sandbox.marketplace.taxamo.com/bulk/api/v3/tax_numbers/validate

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"
            }
        }
    ]
}