“Formula is a free and open-source integrated development environment to create, debug and test your own audio effects the simplest way possible.
Formula can either be used as an effect plugin inside your DAW (VST3 or AU), or as a standalone application. The effects within Formula are made using the C programming language.
Musician 🎸 or sound engineer 🎧 ? See the Formula Cloud section below about how to access hundreds of effects made by developers
VST3, AU, Standalone | Windows, macOS | Free”
Source : soundspear.com