These are free web apps that help you learn music theory and support composing and arranging.
Every tool here is something the developer found genuinely useful over more than 20 years of making music.
Developer: Yoshito Kimura (KHUFRUDAMO NOTES)
Do you need music theory and technical knowledge to make music?
——— Yes. You do.
Does mastering music theory and technical knowledge take tremendous effort?
——— No. It does not.
Just use "O-TO, the music theory web apps".
Stop spending your mind and your time on things that have nothing to do with the essence of creation.