dnSpy (original author: 0xd4d / community)

dnSpy is an open-source .NET debugger, assembly editor and decompiler originally authored by a developer using the handle 0xd4d. The project provides a Windows desktop application that integrates managed code debugging, IL editing, and decompilation into a single toolset, making it widely used by developers for debugging, reverse engineering, and editing .NET assemblies. The primary project sources and releases are hosted on GitHub.

Although the project began under the personal handle 0xd4d, dnSpy has long been maintained and extended by the community; several forks and community-led continuations exist. There is no conventional corporate vendor behind dnSpy — its stewardship is community-driven via GitHub repositories and contributors rather than a commercial company. Users typically obtain the software, report issues, and contribute code through the project's GitHub pages and related community channels.