There are a few brokers who you can use for Algorithmic trading like Master Capital, Edelweiss, Upstox, Zerodha, 5paisa, etc. Once you hone in on the broker, you need to system to setup your Algo trading system.
Most vendors in India provide a standard suite of trading algorithms, which can often be restrictive. If you want custom indicators, parameters, multi instrument strategies, hedging, trailing stop losses, etc. I find developing on top of existing broker systems your custom Algo logic is the best way to go. This way you can run strategies across asset classes and exchanges all from one system as well.
However, you will need to know C++, JAVA and/or C# for this. You also need a lot of expertise and experience in Algorithmic trading technology.
Arque Algo Trader is an Indian firm, which provides this services at a reasonable cost, automating your trading strategies, along with other services to backtest, enhance or add machine learning to your strategies. They also let you run your strategy for multiple clients.