Quote API - 1r/s Order place API - 10r/s Historical API - 3r/s All other endpoints - 10r/s
There is also a 200 order placement per minute limit by the API.
Apart from this, Zerodha RMS has an account level limit of 2000 MIS orders per day and 2000 BO/CO per day limit.
My query is that if I have placed an MIS order with order id "A1", that accounts for 1 order and makes the balance MIS orders for the day to 1999. If I modify the order "A1" 20 times, will it reduce my balance to 1979 for the day or order modification is not a part of the 2000 MIS orders per day?