Kick Assembler Studio is a Commodore Assembly editor that uses Kick Assembler to compile source code.

It’s free to use and can be downloaded from here.
In KAS you can open single files and compile and run them.
Or you can create a project, open a file and add it to the project.
Then next time you open the project, the files will automatically be loaded.
This is a work in progress so bare ind mind that there could be bugs.