[pjscott]

Redis does have an HTTP API, called Webdis. It takes the form of a server that sits in front of Redis, which may be not quite what you were talking about, but I find to be a very clean design. It's fast and full-featured, and is as easy to install as Redis itself. Just get the code, run make, and start the daemon. Maybe add a config file if you want to get really fancy.

http://webd.is/

I've been happy running it in production.

[zrail]

Now this is really interesting. I can think of about a dozen use cases off the top of my head.