For those who are asking for historical data to test their strategies with, here's a free source (where some punyavan has taken the effort to download data from broker and update daily) for 1-min historical data going back to 2008.
dropbox.com/s/pn4qkjk7qidy…
dropbox.com/s/pn4qkjk7qidy…
Now, this isn't clean data. You can't expect 1-min data you get for free to be completely clean and exactly accurate. But this is good enough for any beginner or even an intermediate person to test their strategies with. And since most retail traders trade only TF > 3-5m,
this data should be good enough for you to test your strategies with. Also, you don't need any gimmicks or paid data until you truly have a system in place - well backtested with this free data and you see enough proof in forward trading (paper trading) that it actually works.
TrueData, Globaldatafeeds and other such data vendors charge over 1L for this kind of data. And such data could be erroneous too - but less so than this free data as they are registered data vendors of NSE and get their data directly from NSE and other exchanges.
I don't know if there could be the cleanest data without any errors at all. There's this company called FACTSET which is like an industry leader in data solutions. You could eventually get your data from them too. But all that is largely unnecessary for a beginner.
First things first, don't pay any money to anyone. You don't need any secrets or even any quant's help. Just use this data, use excel, and test basic strategies that you can find online and learn about backtesting thoroughly all the while watching how the strategies perform.
Daily data you can download from quandl.com - that should be mostly clean and free of errors coz it's the data exchange publishes. You can write scripts to scrape bhavcopies out of NSE website and put daily data together yourself.
Intraday wise, if you're trading in a 3-min or 5-min or 10-min timeframe or above, you don't worry about the cleanliness of the data first. Focus on getting a strategy with a decent profitable expectancy - and given this free data available is obtained from Zerodha PI i suppose,
it is decently okay for you to test your strategies. So do that first, then assign certain error % and be very generous with that error assumption - and if your strategy still stands, you got something to trade with.
Then once you make some money trading it consistently and with proper discipline and money management, you can collect high quality data (1-sec data) from a broker like IBKR every month end for your data collection/testing purposes. And if you're lazy you can always shell out
and buy data from a reputed source (or eventually get to a level where you can purchase data from NSE itself and become a data vendor yourself 😅). Until then, work with this free data and free tools available for you. Until you have exploited all the free resources
and the free tools that are also decently sufficient quality, don't go after the paid ones. While paying for stuff may make you feel like you're making some progress, it's an ego trap. If you can't make the best out of what's freely available, what's to say you'll do that by
paying through your nose? So, resign the notion that paid stuff, paid tools, paid courses, etc., are all higher quality or better stuff and first try and make the best out of what's available to you for free. Once you do that, you'll eventually be at a better place to utilize the
paid content to the fullest. One might think that unclean or data with few ticks missing can make a mountain of difference that it might make a strategy unprofitable or something. But your strategy has to suck balls to begin with to become unprofitable with clean data.
I think any decent strategy with TF>=5min would have relatively lesser error rate in output - so you start with that and eventually refine your strategy as you go. Don't go looking for handouts, put in the work and do some digging. Python, Excel, Pandas, R, Backtrader, etc.,
are all freely available. You can download as much data as zerodha or any of your broker terminal gives access to. Start there. And then refine, better your toolset as you go.
