The What-If Tool is meant to be used either in notebooks or through TensorBoard. It is technically possible to have it as a standalone webapp but would require lots of surrounding glue code that isn't documented. We actually do this for our web demos (see them at
https://pair-code.github.io/what-if-tool/explore/#web) with the code in
https://github.com/PAIR-code/what-if-tool/tree/master/wit_dashboard/demo.
But since this isn't a fully supported use-case, we don't have full documentation and tutorials around it. Are you instead able to run your What-If Tool through TensorBoard if you aren't interested in using a notebook environment?