XSTAMPP 4 is a tool for hazard analysis with STPA. STPA is a technique for analyzing systems to identify possible loss scenarios, based on an extended model of accident causation. In comparison to its predecessor XSTAMPP 3, XSTAMPP 4 is a webapplication that you can run in your browser, no installation required. Multiple analysts can work on the same project at the same time.
Developer introduction and documentation available in xstampp-docs.