Nice work building something!

It seems the node stuff only works with express? There are lots of other server frameworks and libraries in the node ecosystem.

The way you configure the token needs some work, too. It really should be passed in in the client code instead of having people edit your library.

You may want to give clients a way to redact or suppress stuff in case they don't want to send any sensitive URLs over.

Have you done any benchmarks to see what sort of load this puts on a client app?