Interface Testing is defined as a software testing type which verifies whether the communication between two different software systems is done correctly.
A connection that integrates two components is called interface. This interface in a computer world could be anything like Application Programming Interface (API), web services, etc. Testing of these connecting services or interface is referred to as Interface Testing.
An interface is actually software that consists of sets of commands, messages, and other attributes that enable communication between a device and a user.