NDB urlsafe keys and REST api requests
Google uses HTTPS internally so I'm not sure you need to worry about it.  
Also, you should probably design your app so that keys are not secret info and such that it is safe to expose them.
I use key IDs for my REST calls, which I believe are 12 digit numbers.  That works as long as you know the entity type.  If you need to specify the entity type, you could add another parameter to your API call.
I was wondering what others are doing to expose REST api endpoints with the datastore (using app engine standard). I want to use urlsafe keys but 1 - I'd rather not pass this data directly as it poses a security risk since app-engine to app-engine calls are exposed over a public ip, and 2 - the keys that are generated are very long and would not be great when multiple need to be passed as a query parameter to form a get request (and would probably exceed browser character limits).
I was thinking maybe using compression of some sort to compress the urlsafe keys which would solve both 1 and 2, but want to see if there is a better way to create REST endpoints. Or if some type of compression method is already baked into ndb?