Yes, You can Buy Today Sell Tomorrow (BTST) in FYERS as Early Payin (EPI) will be done to the exchange on a daily basis. However, you can do BTST in the series mentioned in the below table:
Apart from the above mentioned series, you'll not be eligible for BTST.
Note: Clients have to wait for the shares to be credited into their Demat in order to Sell the same.