Baron is a Bitcoin payment processor that anyone can deploy
github.com
github.com
edit: I also just realized it depends on "bitcoin". It may rely on a running bitcoin core full node to handle the private keys.
That means it does not support deterministic keys. Users will need to be careful to back up their wallet.dat file on a periodic basis.
If there is sufficient demand it would be theoretically possible to include watch-only support so the Baron server need not have private keys online. Ideally this would work with a Hierarchical Deterministic wallet where the server does not need to be periodically refilled with unused addresses.
Hypothetically this could be done today with a javascript library that generates the public addresses as needed. I am not sure if such a library exists at the moment?