Is sign in and sign up are same?
Sign up means "to register; to create an account". In computing, sign in and log in are synonyms. Both mean "to open a session with an account that is already created". There is one difference: the derived noun login "a username; a session under that username" exists, but there is no such noun as *signin.
Is log in and sign in the same?
We can use the phrasal verb “sign in” in the same way as “log in.” But unlike “log in,” “sign in” is common outside of the computer world. As part of security measures in an office building or school, you may have to provide information about yourself before you enter.