[Retra]

Someone might feel inclined to implement their own server that is compatible with the client.

[beaucollins]

Simperium Server: https://github.com/beaucollins/node-simperium-server It's in the proof-of-concept stage so it doesn't persist the data on the server.

[cocktailpeanuts]

Someone that motivated would be better off building their own client as well. In case of Simplenote, server is the most important part, client is just a thin wrapper.