Project Spotlight: Cecil

April 30, 2026 by .NET Foundation Board

Mono.Cecil is a powerful library for generating, analyzing, and modifying .NET programs in ECMA CIL form. In simple terms, it lets you work directly with compiled .NET binaries—without needing to load them via reflection.

With Mono.Cecil, you can:

  • Inspect and analyze .NET assemblies using a clean, flexible object model
  • Modify existing binaries, including metadata and IL code
  • Build advanced tooling such as profilers, weavers, and code analyzers

First released in 2004, Mono.Cecil has become a foundational tool used across the .NET ecosystem. Many frameworks, libraries, and developer tools rely on it under the hood.

If your work depends on Mono.Cecil—directly or indirectly—consider supporting its continued development. Community contributions and sponsorship help ensure its long-term sustainability.

To join the conversation or learn more, discussions take place in the Mono.Cecil Google Group.