We will study half-BPS boundary conditions in 3d N=2 field theories. We will construct simple boundary conditions and study their local operator content using a quantity called the half-index. Using the half-index and 't Hooft anomaly matching as a guide, we study the actions of a variety of 3d dualities on the boundary conditions, including level-rank duality, simple abelian dualities, and Seiberg-like duality. Identifying the dual pairs of boundary conditions, in turn, helps lead to the construction of duality interfaces. This talk is based on arXiv:1712.07654 with with T. Dimofte and D. Gaiotto.