This application produces small wav sounds on every keystroke just like an iPhone keyboard.
For Mac OS, I have already included Clickey.app in /Bundled Applications.
Will require system permissions when you'll run it for the first time.
Using Command Line : (Assuming you have java installed)
git clone https://github.com/piyush0/Clickey
cd Clickey/"Bundled Applications"
java -jar Clickey.jar