[11][12][13][14][15][16] Kastrati has been promoted as a referee in the Kosovo Superliga, the national top-flight, during the 2016–17 season and his debut match was FC Besa vs KF Hajvalia on 8 March 2017.

[18] On 13 October 2020, Kastrati refereed his first international match, taking charge of a 2021 European Under-21 Championship qualifier between Romania and Malta.

[19][20] In September 2022, Kastrati was appointed to referee the 2022–23 UEFA Europa Conference League group stage match between Gent and Shamrock Rovers.

[21] In June 2023, he refereed Kosovo Cup Final match between SC Gjilani and FC Prishtina.

[25] Beyond refereeing, he works as an Information Technology Consultant at the Central Election Commission in Kosovo.