Algo trading is a system of trading wherein simple or complex trading strategies are defined into algorithms which can then execute trades on the basis of the predefined parameters. It executes orders using automated or semi-automated pre-programmed trading strategies/logic and performs it with speed & frequency if required.
FYERS API integration will help you execute the buy/sell instructions from your trading strategies in real-time hence, resulting in better and more accurate order execution. While you can build your own algorithm and deploy it to generate buy or sell signals and you will need to obtain necessary approvals from the exchange.