QuantConnect is a cloud platform for backtesting and deploying algorithmic trading strategies, built on top of its LEAN engine. LEAN itself is actually open source under the Apache 2.0 license and can be self-hosted, but QuantConnect's cloud platform layer — hosted backtesting, live data, brokerage integrations, and collaboration — is a separate proprietary hosted service with its own subscription pricing.
Because the underlying engine is already open, the real choice here is whether you want QuantConnect's hosted convenience or a self-hosted research stack. OpenBB is an open-source alternative for teams whose focus is investment research and data access rather than running LEAN's backtesting engine directly.
FAQ
Is there a free, open-source alternative to QuantConnect?
QuantConnect's own LEAN engine is open source and free to self-host. If you're looking for a broader open-source research and data platform instead, OpenBB is also free and open source.
What's the best open-source alternative to QuantConnect?
For backtesting and algo trading, self-hosting LEAN directly is the closest open-source path since it's the same engine QuantConnect's cloud product runs on. OpenBB is the better pick if your priority is market research and data exploration rather than strategy execution.
What are the top open-source alternatives to QuantConnect?
Browse all open-source alternatives to QuantConnect above, or explore the full Data & Analytics category for more options.