Algo Trading Companies demat accounts and api

https://algotest.in/pricing 

https://bluechipalgos.com/

OI graphs and other comparisons free to use

https://tradingtick.com/options/callvsput

they give algos and data  for trading in their platform

https://app.algobulls.com/

algofox.in - no code automation - 2000 per month

no brokerage

https://flattrade.in/algotrading

shoonya

kotakneo free for api orders