The description relates to an expandable intervertebral spacer configured to engage an intervertebral disk. An example expandable spacer includes a main body, a first endplate, a second endplate, a driving member, a plurality of pins, and an actuation member. The expandable spacer is configured to transition from a first configuration to a second configuration by various structures (e.g., steps, faceted surfaces, curved surfaces, multi-faceted portions) defined on the first endplate, the second endplate, and the driving member.