JAM score is accepted by IIT Delhi & Roorkee
GATE is accepted by IIT Madras.
IIT Kanpur takes a separate written exam based on JAM as well as GATE score (top 250-300 scorers are chosen for written exam; cut-off not available, they send email to shortlisted students).
IIT Delhi also takes a separate entrance exam of its own later in May for 15 additional seats.