Can you elaborate on the security/permission issues? It's something we spend a lot of time thinking about, would love to learn more about your concerns and how we can address them.

I think there are two use cases for URLs as pointers, transient and persistent. In the transient case, you use the URL as a temporary representation, pass it around to the relevant hops, and then fetch it wherever the final resting place may be. In the persistent case (say you're building a web app where users upload content and you want a permanent link), there needs to be somewhere in the line that a service "guarantees" that the link will remain alive and true so that the resource it points to sticks around. So in our case, what we do is if the developer asks for a persistent link, we will take a snapshot of the content and persist it encrypted on our CDN for them, making sure the link stays alive