Most common passwords dictionaries are used by multiple hackers when attempting to guess credentials for users of a given targeted service. Most users aren't aware of the potential impact of having an easily guessable password. Thus it is desired for the service provider to check if the user chosen password is part of a common password dictionary, and ask the user to choose some other strong password.  This API service takes in the hash (sha256) of user password and returns if the password belongs to a common password dictionary.