TradingView

TradingView is a charting platform for equities, forex, futures and cryptocurrency, with a full set of technical indicators and drawing tools running in the browser.

Its scripting language, Pine Script, lets users write custom indicators and strategies and publish them, and the resulting public library is one of the largest collections of shared trading tools anywhere.

Its social layer — published chart ideas with reasoning attached — is worth reading critically: contributors are not screened for track record, and confident presentation is not evidence.