Thinkorswim (by Schwab)

Thinkorswim is widely regarded as the most powerful trading platform available to retail investors. Originally built by TD Ameritrade, it now lives under the Charles Schwab umbrella and remains the gold standard for options traders, futures traders, and anyone who wants professional-grade tools without a Bloomberg Terminal price tag.

The platform offers advanced charting with hundreds of technical indicators, a built-in scripting language (thinkScript) for custom studies, options probability analysis, a sophisticated paper trading simulator, and real-time streaming data. The options chain view, risk profile graphs, and spread builder tools are best-in-class.

Thinkorswim is available as a desktop application, web platform, and mobile app. The desktop version is the most powerful, but the mobile app is surprisingly capable for on-the-go trading. For options and futures traders, there is no better free platform.