Loading .p12 (PKCS#12) cert from browser

My Dash app pulls data from a REST API web service which requires authentication. Currently, I’m pulling in my .p12 file with my key manually in python and using it to make the request. In reality, the user would have the .p12 file installed in their browser and I would want to use that file to make the authentication for the data requests.

Maybe this is more of a Flask question, but I’m just wondering if you have any breadcrumbs on how to implement this.