OpenDMS.NET lets you implement a document management system into a project of your own or as a stand-alone DMS. The API is based on HTTP, so clients are fairly straightforward to develop.
MnemonicFS is an information filing system with a rich API for use by programmers in providing filing capabilities to applications during storage of documents. It builds as a library.
A tool that counts the number of integer points in parametric polytopes.
A diff/patch library for JSON-serialized data structures.