Sputnik is a web front-end for Saci - a document-oriented storage system with history. Saci's nodes can store arbitrary structured data and can be turned into Lua objects. For actual storage, Saci uses swappable modules that all implement the Versium API.
Sputnik extends Saci with Actions. An HTTP request to Sputnik specifies a node, and an action that the node should perform and (optionally) a list of parameters. Unlike many other web applications, Sputnik delegates the resolution of the action to individual nodes.
Sputnik is written as a WSAPI application. It should run on any web server on which WSAPI runs.
Sputnik uses LuaRocks for managing modules and plugins.