GST Verification API: How to Verify a GSTIN
Everything you need to validate a GST number programmatically — decode the GSTIN, confirm the business, and check filing compliance.
A GSTIN (GST Identification Number) is the 15-character identifier every GST-registered business in India carries. Verifying it tells you whether a vendor, merchant or counterparty is a real, active, registered business — essential before you onboard a supplier, extend credit, or raise an invoice.
What does a GSTIN tell you?
The 15 characters are structured: the first two digits are the state code, the next ten are the PAN of the business, and the rest encode the entity number and a check digit. Because the PAN sits inside the GSTIN, a single PAN can map to multiple GSTINs — one per state the business operates in.
What the GST Verification API returns
- Legal name and trade name of the business.
- Constitution — proprietorship, partnership, private limited, etc.
- Registration status — active, cancelled or suspended.
- Registration date and state jurisdiction.
POST https://api.bilapi.com/v1/gst-verification-api
X-Bilapi-Api-Key: <your_api_key>
Content-Type: application/json
{
"gstin": "27ABCDE1234F1Z5"
}{
"status_code": 200,
"success": true,
"data": {
"legal_name": "ACME TRADING PRIVATE LIMITED",
"constitution": "Private Limited Company",
"registration_status": "Active",
"state_jurisdiction": "Maharashtra"
}
}Going further: filing status and compliance
Basic verification confirms the business exists and is registered. For credit and risk decisions you often want to know whether the business is actually filing its GST returns. The GST Advance Verification API adds filing status, recent return history and a compliance signal — a business that files on time is a lower-risk counterparty than one that is dormant.
Verifying GST by PAN or mobile number
You do not always start with the GSTIN. If you have the business's PAN, the GST PAN Search API returns every GSTIN registered against it across all states. If you only have a phone number, the Mobile to GST Number API maps it to the linked GSTIN — handy for confirming a merchant who signs up with just a mobile number.
Best practices
- Check registration_status, not just existence — a cancelled GSTIN is still a real number.
- For lending, use filing status as a risk signal, not just the registration.
- Store the legal name and verification timestamp for your compliance trail.