An Australian GST number is simply an Australian Business Number (ABN) which is registered for GST. Once registered, a business can charge GST on the products and services it provides and also claim back GST against expenses made for the business.

In order to verify that a transacting partner on the other end is actually registered for GST, a provider of goods and services may decide to validate the ABN against the official government registry.

How to Validate an Australian GST Number

The quickest way to validate an ABN is to use the ABN Lookup web service provided by the Australian Business Register (ABR).

Enter a business number (without the ‘ABN’ prefix) and look for the entry ‘Goods & Services Tax (GST)’. This line item states whether the business is registered for GST or not.

Here’s an example for ABN 49 004 028 077 (BHP GROUP LIMITED):

Official ABN details from the Australian Business Register.

Manual lookups may no longer be feasible once you want to perform checks in real-time at scale or during an online checkout process. This is where you should consider integrating an API like Vatstack for automated ABN validation.

Create a free account to obtain a unique API access key. With the access key, you can start interacting with our API to check official records automatically.

Send a POST request to the validations endpoint containing an ABN and the API will respond with official ABN details.

Validation API Response

The following snippet shows an example of how the API’s response looks like for the business we queried manually just now. Look for the valid boolean to determine whether the business is registered for GST.

{
  "id": "5ec59f3a03e009670196d7f8",
  "company_address": "VIC 3000",
  "company_name": "BHP GROUP LIMITED",
  "consultation_number": null,
  "country_code": "AU",
  "created": "2020-05-20T21:20:58.241Z",
  "query": "ABN49004028077",
  "requested": "2020-05-20T21:20:58.042Z",
  "type": "au_gst",
  "updated": "2020-05-20T21:20:58.241Z",
  "valid": true,
  "valid_format": true,
  "vat_number": "49004028077"
}

You can learn more about our validations endpoint in the API reference. If you need more information, please do not hesitate to reach out. We’re happy to discuss ways we can help you automate your business processes revolving around VAT and GST.