Workbench

Checks porta-pages apps against the repo's conventions, using only what your browser already has. Nothing you pick is uploaded, and nothing in the files is run.

Pick the repo folder, or pick or drop .html files.

From a folder, only the .html files at its top level are checked. The browser still lists every file in it first, so a folder with node_modules inside takes a moment.

Another site has to let other pages read its files (CORS), as raw.githubusercontent.com does for public repos.