Anybody are conscious of a in a commercial sense available file based storage system that fits the next needs:

Shouldn't require installation Ought to provide APIs to read to the storage system, ideally .internet APIs Compensated/Free (in either case it ought to be supported) Ought to be fast and efficient

Essentially I'm searching for something with database like functionality using the least footprint.

Have a look at Sqlite. It is the conventional solution for any file based database solution - it's even built-in towards the apple iphone, Opera and several other much talked about software/products.

My Google-fu provided this straightforward tutorial of utilizing Sqlite with .internet: sqlite-on-dotnet-in-3-mins

Try MongoDB it is a file based document database. Setting up to control your emotions by copying it's files and contains a C# driver to seeOrcreate data from this.