Hello. It looks like you support HTTPS as I've successfully used HTTPS via CURL (and a modified version of the Node.js package) to convert PDFs.
The only issue is that your Node.js package by default does not use HTTPS by default which is what is preferred.
Please see my pull request
and give ATTN for the developers for any edits so we can get it merged in.. I would prefer to link to the official repo rather than a fork!