No, it's not possible to get into BITS Hyderabad without BITSAT. BITSAT is the only admission route for B.E./B.Tech programs at all BITS campuses (Pilani, Goa, Hyderabad).
there is no JEE Main, board marks, or any alternative test that can substitute BITSAT for BITS admissions. BITS is a completely autonomous deemed university that runs its own entrance exam with strict eligibility.
the only exceptions where BITSAT isn't needed:
so if you want BITS Hyderabad, you have to give BITSAT. the exam covers Physics, Chemistry, Math, English Proficiency, and Logical Reasoning. It's conducted online at test centers.
one important thing — BITS also looks at 12th marks as eligibility: you need 75% aggregate in PCM + English to be eligible for admission after qualifying BITSAT. if you have the BITSAT score but not 75% in 12th, you won't get the seat.
The BITS campuses intake B.E. students through three methods. These are-
Thus, it is possible only for a board topper to get into BITS Hyderabad without giving BITSAT.