Steamworks.NET is a C# Wrapper for Valve’s Steamworks API and is completely free and open source under the permissive MIT license! A primary goal is to be as easy to get started as possible.
Steamworks.NET was designed to follow as close to the native Valve provided C++ API as possible and boasts 100% coverage of the native Steamworks API across all interfaces!
Stats & Achievements
Utilizing Steamworks Stats and Achievements API provides an easy and effective method of storing persistent gameplay stats and roaming Achievements.
Steam provides a solid set of Leaderboard focused APIs so that your players can see who’s the fastest, the strongest, or just the downright deadliest!
User Authentication & Ownership
A variety of different API’s are provided to manage User Authentication and Ownership.
Steamworks provides an excellent set of tools for multiplayer Matchmaking perfect for both server based and lobby oriented games.
The Steam Community API is a set of APIs which allow you to utilize the Steam Overlay to it’s fullest and access information about other players including but definitely not limited to: Persona Name, Avatar, and Group Memberships.
A networking abstraction layer is provided to take the difficult logistics of sending data over the internet. Never worry about connectivity issues caused by things like port-fowarding ever again!
The Steam Cloud provides the simpliest possible way to sync your save-game data to the cloud allowing your players to keep their in-game progress without hassle when switching between devices or even after a nasty computer crash!
VAC is there to provide you with an additional layer of security in your competitive multiplayer experiences. It is very similar to a virus scanner and has maintains a list of known cheats to detect.
And many more features!
Infact Steamworks (and therefor Steamworks.NET by extension) contains far too many features to list!