Saxon Runner
Live
XSLT and Saxon on Windows, no command line.
Pick the stylesheet and the XML, hit Run: Saxon's result and errors land in two separate tabs, and clicking an error line takes you straight to the right spot in the editor. It re-runs on its own when you save the file, remembers recent runs and, if you have Ollama, offers a local assistant that checks and completes your XSLT without the code ever leaving your computer. It installs and updates itself.
With Bais