Fracturing systems with frac valves for controlling flow of fracturing fluid are provided. In one embodiment, a fracturing apparatus includes a frac valve having a housing with a bore to convey fracturing fluid, a seal disposed within the bore, and an actuator coupled to control movement of the seal. The actuator can be disposed within the bore so as to move the seal between a closed position in which the seal blocks fracturing fluid flow through the bore and an open position that allows fracturing fluid flow through the bore. Additional systems, devices, and methods for fracturing are also disclosed.