What are the alternatives to MAS? I've been considering distributing a small OSX app at a fairly low price based on its value. Are there any good ways to sell l

What are the alternatives to MAS? I've been considering distributing a small OSX app at a fairly low price based on its value. Are there any good ways to sell low-priced licensed software that support pushing updates to users easily? Edit: I should mention that in my particular case, the app is an Electron (formerly Atom Shell) app, so a solution that involves an ObjC library might be a bit difficult to implement.