Trading with rsi index

Not realiable at all as indicators are price derivates, you should never make a trading decision based on an indicator (rsi, stochastic, ecc...). Learn to read naked price charts, maybe combined with a couple of Moving averages

Because the RSI calculation involves a ratio, it eliminates the problem of needing large amounts of historical data. But because a ratio is used in its calculation, it is more volatile and erratic. Shorter RSI periods result in more timely signals along with a larger number of whipsaws. Longer RSI periods result in fewer signals which are less timely and less profitable because of delayed entry and exit.

Here's the catch with technical indicators like RSI. They can provide information like support and resistance, trend, and current momentum but they are just reflection of past price and they predict absolutely nothing going forward. It's like looking in the rear view mirror to see where you have been. Any trade taken based on them is based on the hope that the trend continues.