To access e-Invoicing through APIs, the taxpayer has to create API credentials on the e-Invoice portal. The API credentials are to be passed in the e-Invoice Authentication API to generate the 6-hour access token.
Steps to create API credentials
Step 1 - Log in to your Account on https://einvoice1.gst.gov.in/.
Step 2 - Navigate to User Credentials > Create API User.
Step 3 - Please enter the OTP received by the user.
Step 4 - Once you enter the OTP, you can click on "Through GSP".
Step 4 - Select the GST Provider. In this case, add "Vay Network Services Pvt. Ltd." and then enter the username and password and then click on "Submit".
Step 5 - After clicking Submit, you will be able to see the list of GSP registered. Use this Username and password in the e-Invoice Authentication APIs.