The Sukhoi Su-57 (Russian: ????? ??-57; NATO reporting name: Felon)[5][6] is a twin-engine stealth multirole fighter aircraft developed by Sukhoi.[7] It is the product of the PAK FA (Russian: ??? ??, short for: ????????????? ??????????? ???????? ????????? ???????, romanized: Perspektivnyy Aviatsionnyy Kompleks Frontovoy Aviatsii, lit.?''prospective aeronautical complex of front-line air forces'') programme, which was initiated in 1999 as a more modern and affordable alternative to the MFI (Mikoyan Project 1.44/1.42).
Sukhoi's internal designation for the aircraft is T-50. The Su-57 is the first aircraft in Russian military service designed with stealth technology and is intended to be the basis for a family of stealth combat aircraft.

A 5th-generation multirole fighter capable of aerial combat as well as ground and maritime strike, the Su-57 incorporates stealth, supermaneuverability, supercruise, integrated avionics, and large internal payload capacity.[8] The aircraft is expected to succeed the MiG-29 and Su-27 in the Russian military service and has also been marketed for export. The first prototype aircraft flew in 2010, but the program experienced a protracted development due to various structural and technical issues that emerged during trials, including the destruction of the first production aircraft in a crash before its delivery.

After repeated delays, the first Su-57 entered service with the Russian Aerospace Forces (VKS)[N 2] in December 2020.Not counting prototype test aircraft, a total of 11 had been produced as of December 2022.