Abstract: A unibody transtibial prosthetic device includes a socket personalized for a specific patient's residual limb. A pylon extends from the socket, the pylon being a unitary polymer structure of interconnected elongated supports having open spaces therebetween. The device also includes a foot-ankle complex, the foot-ankle complex being a unitary polymer extending from the pylon, the foot and ankle unitary structure being shaped to provide multi-axial dynamic flex to enable dorsiflexion, plantar flexion, inversion and eversion motion for smooth symmetric gait performance and energy capture and return. The socket, pylon and foot-ankle complex are portions of a unibody.