QuantConnect provides an algorithm backtesting tool and financial data so engineers can design algorithmic trading strategies. We democratize algorithm trading technology with a fully open-source platform to empower investors.Our community of 220,000 engineers designs investment strategies in Python or C# to trade through to their brokerage accounts. Each month we do $1-2B in notional volume, and serve 5,000+ users.
QuantConnect (quantconnect.com) has 65 customer reviews on Five Star Index, with an average rating of 4.1 out of 5.
Also known as
quantconnect.com
Website
quantconnect.com
Category
Investments & Wealth
Location
Lewes, Delaware
Listed on Five Star Index
2026
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Most recent review: October 2026.
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QC is an extremely difficult system to use for the average trader (I'm comparing it to competitors products with respect to coding, flexibility and ability to live trade) Given reasonable investigation the data it uses for backtesting is questionable (they cut you off if you look at too much data) and most importantly it only allows you to back test and live trade on a small list of underlyings: good for Bitcoin and fx (I assume but don't know) but NOT for equities and listed securities and most futures.
TI
tickz
buggy, slow, opaque, poor docs and expensive
cannot recommend
Cons:
- lack of transparency (deleting critical statements in forum)
- alpha market is a joke. there are no trading firms paying license fees for algos.
- many alphas in market are likely overfitted
- setting up LEAN for local machine is buggy and complicated
- unnecessarily complex API, difficult to learn, poor docs (at least for python developers), LEAN is C# but most users need Python
- research (notebook) is slow, throwing time out errors when analyzing large datasets
- backtesting is slow when trading many assets with high resolution data, throwing time out errors all the time
- web ide limited, poor debugging tool
- switching between local (Skylight) and cloud is tiresome, no efficient workflow for algo development
- limited possibilities to analyze and visualize backtest results
- buggy API, bugfixes take too much time
- expensive for retail/invididuals (default pack = +800$/year)
Pros:
- community provide support in forum
- open source (LEAN)
- large and reliable database including tick data for many securities
- L1 quote data available for equities
- live trading
- event-driven backtesting engine
- all-in-one ecosystem (research, backtest, live trading, data, optimization)
BR
Bob R.
Shady site
Shady site not sure if the team behind are trustworthy with holding your algos data. I found other frameworks like backtrader that are easier to pick up and get working with quickly than LEAN. LEAN is poorly documenting making learning a huge hurdle. Also, I question the stability of their site because of the amount of bugs you can find in their UI and some that I encountered in plotting during backtrading. If you need an online IDE, Quantopian is far more reliable and documented and quicker to work with but still could have issues with data privacy.
