You need to enable API access from your account in the GSTN portal to connect the FlexiPayment Platform with the GSTN portal securely. 

To enable API access: 

• Log in to GSTN portal at www.gst.gov.in.
• Click your name in the top right corner of the page and select My Profile. 

Click the Manage API Access from the Quick Links. 

• Click Yes and select a duration from the dropdown. 
• Click CONFIRM.

Duration for keeping GST API Access active.

You have the option to keep your API session active for a minimum of six hours and up to a maximum of 30 days without the need to enter an OTP. If desired, a taxpayer can select a longer session to allow for an active session with the GST portal without requiring an OTP. Conversely, a taxpayer may choose to terminate a longer API session and enable API access for a shorter duration.