Mobile to GST Number
Map a mobile number to the GST-registered business behind it in one API call.
What is the Mobile to GST Number?
The BILAPI Mobile to GST Number API finds the GSTIN(s) linked to a mobile number, letting you identify the registered business behind a phone number during merchant or vendor onboarding.
It is used by B2B marketplaces, lending and invoicing platforms to confirm that a merchant who signs up with a phone number is a genuine GST-registered business, and to auto-fetch their GST details without asking for the GSTIN.
Pass a 10-digit mobile number and receive the linked GSTIN(s) with business details as JSON. Billed only on a successful lookup.
What the Mobile to GST Number returns
Every successful call returns a clean, predictable JSON envelope. The data object includes the fields below (exact fields vary by record availability).
| Field | Description |
|---|---|
mobile | The mobile number that was searched. |
gstin | GSTIN linked to the mobile number. |
legal_name | Legal name of the registered business. |
state | State of the GST registration. |
registration_status | Active/cancelled status of the GSTIN. |
Sample request & response
Call the endpoint with your API key in the X-Bilapi-Api-Key header. The same request shape works in the free sandbox and in production.
POST https://api.bilapi.com/v1/mobile-to-gst-number
X-Bilapi-Api-Key: <your_api_key>
Content-Type: application/json
{
"mobile": "9876543210"
}{
"status_code": 200,
"success": true,
"message": "GSTIN found",
"data": {
"mobile": "9876543210",
"gstin": "27ABCDE1234F1Z5",
"legal_name": "ACME TRADING PRIVATE LIMITED",
"state": "Maharashtra",
"registration_status": "Active"
}
}Key features
Real-time results
Sub-300ms median response so GST checks never slow your onboarding funnel.
Predictable JSON
The same clean response envelope as every BILAPI endpoint — parse once, reuse everywhere.
Only pay for hits
Invalid inputs and failed lookups are never charged to your wallet.
Secure by design
TLS 1.3 in transit, PII tokenisation at rest and a full audit log on every request.
One key, every API
Sandbox to production on a single key — no per-vendor contracts or integrations.
Built to scale
99.9% uptime target with bulk and webhook-friendly workflows for high volume.
Where it's used
Customer onboarding
Auto-fill and validate identity during signup to cut drop-off and manual review.
Lending & underwriting
Add a verified data point to credit decisions and reduce first-party fraud.
Fraud & risk
Flag mismatches and synthetic identities before they enter your system.
Compliance & audit
Keep a tamper-evident trail of every verification for KYC/AML reviews.
How it works
Create a free account
Sign up on the BILAPI console and get a live API key instantly.
Send a request
POST the required GST fields to the endpoint with your API key in the header.
Get structured JSON
Receive a clean, predictable JSON response in milliseconds.
Plug into your flow
Drop the result straight into onboarding, underwriting or risk decisioning.
Frequently asked questions
What does the Mobile to GST Number API do?
It finds the GSTIN(s) linked to a mobile number and returns the registered business name, state and status — mapping a phone number to a GST-registered business.
What is the input?
A single 10-digit Indian mobile number.
Why is this useful in onboarding?
It lets you confirm a merchant who signs up with a phone number is a real GST-registered business, and auto-fetch their GST details without asking for the GSTIN.
Do I pay for a no-record result?
You are billed per successful lookup from your wallet; failed lookups are free.
Is a sandbox available?
Yes, every account includes a free sandbox before production.
Related Business Verification KYB
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