Systems, methods, and computer-readable media are disclosed for mesh flaps for container capacity detection in sortation systems. In one embodiment, an example system for use with an item sortation machine may include a rotatable flap comprising a mesh grid coupled to a frame, where the rotatable flap is disposed adjacent to a container of items in the item sortation machine, and a sensor disposed adjacent to the rotatable flap, where the sensor is configured to sense an item protruding out of the container. The mesh grid may have a set of metallic wires that intersect to form the mesh grid, where the set of metallic wires form a geometric pattern.