What is an Interface?

An interface in Go is like a contract that defines what behaviors a type must have, without specifying how those behaviors are implemented. Think of it as a collection of method signatures that describes what something can do.

To understand interfaces better, imagine a power outlet in your home.

The outlet has a specific shape and provides electricity, but it doesn't care what device you plug into it. Whether it's a lamp, a phone charger, or a computer, any device that has the right plug shape can connect and receive power. The outlet defines the "interface" - the requirements for connection.

In Go, an interface works similarly. It defines a set of method signatures that a type must have to "plug into" that interface. Any type that has all the required methods automatically satisfies the interface, regardless of what else that type might do or how it implements those methods.

This concept is powerful because it allows you to write code that works with any type that can perform certain behaviors, making your programs more flexible and reusable. Just like how different devices can all use the same power outlet, different Go types can all satisfy the same interface as long as they have the required methods.