Extreme programming (often called 'XP') is a way of writing computer programs that makes sure that the program works correctly the first time. To make sure the program works correctly, extreme programming encourages programmers to test the program as they write it, instead of waiting until they are finished to test it. This way, if there are any mistakes, they can be fixed quickly and easily. Extreme programming also encourages programmers to use special tools to help them make sure their code is consistent, which means that the same code looks and works the same way every time. Finally, extreme programming encourages programmers to collaborate with each other to work out any tricky problems that come up.