IBInteractive Brokers LLC · Financial analysis & investing
In-depth entry Programmatic trading and market-data access to Interactive Brokers accounts through the TWS API, the REST-based Web API and FIX
ProprietaryUsage-basedPaidLocalRedirected QQuantConnect Corporation · Financial analysis & investing
In-depth entry Algorithmic trading platform built on the open-source LEAN engine, with cloud backtesting, research notebooks and brokerage-connected live trading
Apache-2.0FreemiumPaidLocalNov 2, 2026 QQuantLib project (Luigi Ballabio and contributors) · Financial analysis & investing
In-depth entry Open-source C++ library for quantitative finance covering instruments, term structures, pricing engines and calendars, with Python and other bindings
BSD-3-ClauseOpen sourceFreeLocalNov 2, 2026