Both market data and websocket functionalities necessitate the use of instrument keys. As market quotes are accessed using these instrument keys embedded in the URL, standard URL encoding is essential to format them correctly.
The provided instruments file includes these unique instrument keys that are indispensable for the API’s operation.
For further understanding of why instrument keys are selected over alternatives, such as NSE symbols, you can refer to this detailed explanation: NSE Symbols Should replace Instrument Key.