# GST Request OTP API: Start GST Portal Login | FastKYC

> Request a GST authentication OTP using a taxpayer's GST username, to start consent-based GST portal verification from inside your own onboarding flow.

Source: https://www.fastkyc.com/apis/gst-request-otp/

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[Merchant APIs](/apis/merchant/)

# GST Request OTP API

Request a GST authentication OTP using a taxpayer's GST username, to start consent-based GST portal verification from inside your own onboarding flow.

[Book a Demo](/book-demo/)

Category

[Merchant APIs](/apis/merchant/)

## What the GST Request OTP API does

GST Request OTP starts GST portal authentication. You send the taxpayer's GST username and an OTP is requested so the taxpayer can confirm access.

It is the first half of a two-step flow: the business proves it controls the GST account by entering the OTP, which you then validate with GST Submit OTP.

## Where teams use the GST Request OTP API

1.  Starting consent-based GST verification during merchant onboarding
    
2.  Confirming a business controls the GST account it declares
    
3.  Opening GST portal access for return and filing data
    

## Frequently Asked Questions (FAQs)

What do I need to send?

The taxpayer's GST username.

What happens next?

The taxpayer receives an OTP, and you validate it with GST Submit OTP to complete authentication.

## Start verifying with the GST Request OTP API

Book a walkthrough and we will show the call, the response and how it fits your onboarding flow.

[Book a Demo](/book-demo/) [Browse All APIs](/apis/)

-   One API key for every check
-   Verified against official Indian records
-   Built for onboarding at scale