If you’ve read our guide to algo trading mistakes and you’re ready to actually build something, the first real decision you’ll hit isn’t strategy logic. It’s which broker’s API you’re going to build on. All three of India’s major retail options work, but they differ enough in cost, documentation, and what you get for free that picking blind can cost you either money or a lot of debugging time.
Zerodha Kite Connect
Kite Connect has been around the longest and it shows in how mature the infrastructure is. Zerodha’s own numbers put it at over 500 million API requests processed daily and 100 million live ticks per second across their user base, which matters less as a bragging point and more as a signal that the plumbing has been stress tested for a decade.
Pricing changed recently and it’s worth knowing if you’ve read older comparisons that still quote the old rate. There’s now a free Personal tier that covers order placement, GTT, alerts, and portfolio and margin management. If you want real time WebSocket streaming and historical candle data, that’s the Connect tier at 500 rupees a month. That’s a meaningful drop from what Kite Connect used to charge, so if you dismissed it as expensive a year or two ago, it’s worth another look.
The tradeoff is that you need an existing Zerodha trading account, and the documentation, while solid, assumes you’re comfortable reading API references rather than hand holding you through setup.
Angel One SmartAPI
SmartAPI’s pitch is straightforward: it’s free, full stop. No subscription tier, no paywall on historical data. You get SDKs across Python, Java, NodeJS, Go, C#, .Net, and PHP, which is a wider spread than either of the other two offer out of the box.
The catch is less about SmartAPI itself and more about needing an active Angel One account to use it, same as the others. If you’re choosing a broker specifically to trade through your algo rather than adding API access to an account you already have, SmartAPI is the cheapest entry point of the three for getting live data and order execution without paying anything beyond your normal brokerage.
Upstox API
Upstox’s developer API is also free to create and use for market data and order placement. Where it gets more complicated is brokerage on API orders specifically. Upstox ran a promotional flat rate of 10 rupees per order for algo trades, separate from its standard brokerage, but that offer had a published end date and doesn’t appear on Upstox’s current standard charges listing anymore. If you’re budgeting per trade costs for a high frequency strategy, don’t assume the discounted rate still applies. Check Upstox’s brokerage charges page directly before you model your cost per trade, since this is exactly the kind of detail that changes without much warning and quietly wrecks a strategy’s real world margins even when the backtest looked fine, the same trap we covered in the algo trading mistakes post.
How to actually choose?
A few practical filters help more than a feature by feature checklist:
If you’re already trading through one of these three brokers, start there. Moving your capital to a new broker just for API access adds friction and account transfer delays that aren’t worth it unless there’s a real cost or feature gap.
If you’re trading high volume and cost per order matters a lot, run the actual math on current brokerage rates for each broker rather than trusting whatever number a blog post from last year quotes, ours included. Rates on all three have shifted at least once in the past year.
If you want the widest language support for your own stack, Angel One’s SDK list is currently the broadest.
If you want the most battle tested infrastructure for high frequency or high reliability needs, Kite Connect’s track record is hard to match, and the new lower pricing removes what used to be the main objection to it for smaller retail budgets.
None of these are wrong choices. They’re built for slightly different priorities, and the ultimate guide to algo trading in India covers how to think about the rest of your stack once you’ve picked one. For the API layer itself, the honest answer is to check current pricing directly on Zerodha’s product page, Angel One’s SmartAPI documentation, and Upstox’s trading API page before committing, since all three have changed terms within the last year.
