Complex, difficult API, slow backtesting Extremely slow backtesting and very complex APi with bad documentation - be ready to spend many hours trying to understand the overly complex API that is changing all the time. And did I mention that support costs? So if a anything is complex you won't get answers from the staff unless you PAY them. I give them 2 stars as they have reasonably reliable data. The platform itself is only worth one star. note: if you ask about slowness or any other thing negative on their forum they delete the posts.

Can only say good things! Over two (fun!) years the QuantConnect team have assisted me in (1) My programming...which at the beginning was all but non-existent. With this, the customer support, community help and other resources e.g. GitHub provided me with the required information to develop my algos. (2) Connectivity....I can connect one of my algos to one of my Interactive Brokers accounts in about 2 minutes. Its that easy. (3) Ability to license....Many of the systems I have developed over the last couple of years and submitted to the AlphaStreams marketplace are being licensed. Like any other endeavor in life - this takes hard work and a lot of effort. I have had no problems with backtest times - but obviously the times will depend on the amount of data being crunched in the background. So Im very happy - a friendly bunch of people doing real innovative stuff. I cant wait what the next few years bring!

Long time believer, first time promoter. I've been using Quantconnect for about two years but they've just released new capabilities for options research, based on user feedback, that prompted me to add a review. They listen to, care about, and build new features for their users (free features). Highly recommend.

This is the best platform for… This is the best platform for individuals. I seldom subscribe to 'pro-account' things, but I did for this one. The dirty stuff like data cleansing, backtesting framework, error handling is done by them and I can focus on the fun stuff, printing money.

Great technology, accessible team, invaluable supporters of the ecosystem QuantConnect has been an invaluable partner for my personal trading and for a university class that I teach. The community is incredibly supportive, and the leadership team are accessible which is almost unheard of in trading platforms these days. In my class, my graduate level students have been able to personally engage and implement constructs like Fama French factors, and QuantConnect has been an active supporter to facilitate my students learning. It's incredible to join the community, have access to a variety of detailed trading algorithms, instructional videos, and see my students feel confident implementing week-to-week. I don't think there's anything like QuantConnect out there today, and I'm a big supporter of their efforts. I can't imagine my own trading or teaching my class without it!