EDG is now open source. Here’s what comes next.

To the C++ community,

Many C++ developers have never heard of EDG, but a lot of you have used it. For decades, the EDG C++ front end has worked inside well-known compilers, security products, code analysis systems, and developer tools. It parses C++ source, checks the language rules, and produces a representation that other tools can analyze or translate.

On September 30, 2026, EDG made its source code public, and selected the C++ Alliance as its fiscal sponsorship partner.

The code is available under the Apache 2.0 license with LLVM exceptions. This permissive license allows commercial use, including incorporating EDG into proprietary products, subject to terms. For companies building C++ tools, this provides an ideal option for a front end that adapts to your needs.

EDG is also an ideal resource for learning how compilers work. For roughly 30 years, a small team of leading compiler engineers has developed a codebase with a clean structure and extensive documentation. It’s very easy to see how it handles a language feature, and you can examine the relevant tests and experiment with changes.

We’re excited about ways the community can make it even better. EDG has experimental support for reflection for C++26, which lets programs inspect information about types and declarations at compile time. Additional work on that implementation is one area for contributions. Other areas include coroutines, and exploring an LLVM back end alongside the existing back end that generates C. These are just some thought starters, we’re excited to see what the community comes up with.

John Spicer and the EDG team led the transition. EDG’s experienced engineers are the initial maintainers, and John chairs the Fiscal Sponsorship Committee, which will include C++ veterans from the user community.

The Alliance will help support the infrastructure and funding the project needs, much as we do for Boost. We want to help more people get started in compiler development. Reading code, investigating a test failure, and learning why an implementation behaves the way it does are useful steps toward becoming a contributor.

Existing EDG users bring the experience the project needs: real-world code, difficult test cases, and knowledge of the tools built on it. New contributors bring questions and ideas that help improve the code and its documentation. Making the repository public is a start, but keeping EDG useful will take maintenance, testing, documentation, and funding. We can bring more people into the project, and we welcome help with all of it.

Donations and sponsorships from people and organizations that value EDG will help sustain its maintenance and development. If you’d like to support that work, get in touch at [email protected].

Take a look at EDG’s project site, source on GitHub, and John Spicer’s EDG transition letter. If you use EDG, build C++ tools, or want to learn how compilers work, we want to hear from you.

Here’s to what comes next,

Harry Bott
CEO, C++ Alliance

P.S. A few perspectives on why EDG matters:

Testimonials were provided in a personal capacity.