Robert Sanchez signed his first professional contract for the Seagulls in June 2015 and has since established himself as first-choice goalkeeper in the club's under-23 team.
The goalkeeper, who was born in Cartagena, Spain, started his career playing in Levante's academy, before moving to England at the age of 17.
The Spaniard impressed during the 2016/17 Premier League 2 Division 2 season with a number of positive performances, and featured three times in the Checkatrade Trophy, making a string of fine saves against Coventry City in the knockout stages.
Sanchez then helped the Seagulls secure promotion to the Premier League 2 Division 1, via the play-offs, before moving to Forest Green Rovers on loan for the 2018/19 campaign.
He played 17 times for the Gloucestershire club, who reached the Sky Bet League Two play-offs, while also featuring five times for the Seagulls in the PL2 after returning from his loan spell.