A gas turbine engine includes a plurality of airfoil vanes situated in a circumferential row about an engine central axis. Each of the plurality of airfoil vanes include a first platform, and a second platform, and an airfoil section therebetween. A face of the first platform includes a trailing edge recess and a leading edge recess. The trailing edge recess and leading edge recesses of adjacent ones of the first platforms together define a slot. A sealing element situated in each slot. The sealing element has a geometry that tracks the geometry of the slot such that the seal is trapped in the slot by a form-fit relationship in circumferential and axial dimensions by a form-fit relationship between the sealing element and the slot. A method of sealing a plurality of airfoil vanes is also disclosed.