After being in the youth ranks for eleven years, Alanís made his debut for Argentine Primera División side Belgrano in October 2014 against Banfield; coming on late in a 2–2 draw. In his first three seasons with the club, Alanís made sixteen appearances in all competitions. After ten further appearances in his fourth season, 2016–17, he failed to play during 2017–18. On 16 January 2018, Alanís joined Arsenal de Sarandí on loan. He scored his first career goal for Arsenal against Patronato in April 2018.