curl --request POST \
  --url https://api.sandbox.co.in/gst/compliance/e-invoice/tax-payer/authenticate \
  --header 'Content-Type: application/json' \
  --header 'authorization: <api-key>' \
  --header 'x-api-key: <api-key>' \
  --data '
{
  "username": "{{irp_einv_username}}",
  "password": "{{irp_einv_password}}",
  "gstin": "{{irp_einv_gstin}}"
}
'

{
  "code": 200,
  "data": {
    "ErrorDetails": null,
    "InfoDtls": null,
    "Status": 1,
    "access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ0YXhwYXllci1zZXNzaW9uIiwiZ3N0aW4iOiIyNEFCS0NTMjAzM0IxWlYiLCJpYXQiOjE3MTI5NDQxMDAsImV4cCI6MTcxMjk0NzcxMX0.sandbox-signature",
    "expiry": 1708693832000
  },
  "timestamp": 1763446641000,
  "transaction_id": "db0435d0-2a7d-42b2-9b44-94eef880bf60"
}