DiceRoller is a library for .NET which enables rolling dice. It supports a robust syntax with lots of features, as well as customization to add additional features beyond what is offered in the library itself in the form of custom functions and macros.
If you're curious on how to format dice expressions with the library, check out the Dice Reference.
If you are a developer and want to use this library in your own project, grab the DiceRoller package from NuGet via
Install-Package DiceRoller and then see the API documentation (or check the Dice namespace reference as a starting point). You can also grab the source code from GitHub.
For version history, check the Changelog.