Not sure what howutrade.in would charge but Zerodha api is Rs.2000/month, isn't it? That's Rs.24,000 per year whereas the above vendor is selling his product for Rs.5,000 per year.
Personally, I was considering it but unfortunately, he doesn't seem to support equity futures yet. Given that you seem to be in the know of technical things, have you personally tried howutrade's services? If yes, how was your experience in terms of support & customer-friendliness?
As for Upstox api, not sure what's going on now since their thread seems to be inactive now but even until a few months ago, there were a lot of complaints about their api being below par with problems galore.