interactive brokers api

I am looking for a cheapest trading api and came across zerodha, upstox and IB. Zerodha is 2000rs, upstox 650 and IB is free but it needs opening an account with more than 30k and also no support for margin. I am planning to invest less than ten thousand so IB is not in my radar now. Between...

Any people with experience writing to it, I have a small project to get implemented. I will share profits if project is successful and also willing to pay a fee.