what is the difference between ui and api testing code example

Example: ui testing vs api testing

User interface testing is basically testing
the graphical user interface. The focus of UI
testing is on the look and feel of the
application. In the UI main focus is on
how users interact with app elements like
images, layouts etc.
On the other hand Api testing allows the 
communication between two software systems.
API testing works on backend also known
as backend testing.