Hello @smrtsaravanan ,
Apologies for the delayed response. We have introduced OI Data for Nifty and Banknifty via Market Data API and Websocket Streaming 2.0. Please have a look.
https://smartapi.angelbroking.com/docs/Historical
https://smartapi.angelbroking.com/docs/WebSocket2
If you have any other issue, please share request and response on smartapi@angelbroking.com.
Thank you.
SmartAPI Team