PIN-based authentication is a security and usability feature for Betfair's mobile applications. It allows you to quickly login to your account by typing a 4 digit. Sign up for a £30 FREE bet with Betfair. Cash Out your In-Play bets, place a Multiple and get the best value. We also offer Games, Poker, Bingo and Casino. Already have an account with Betfair? Log in to your account and get access to your favourite betting markets.