The Hayward metric is the simplest description of a black hole which is non-singular. The metric was written down by Sean Hayward as the minimal model which is regular, static, spherically symmetric and asymptotically flat.[1] The metric is not derived from any particular alternative theory of gravity, but provides a framework to test the formation and evaporation of non-singular black holes both within general relativity and beyond. Hayward first published his metric in 2005 and numerous papers have studied it since.[2][3][4][5]