This package provides new environments similar to the environments matrix, pmatrix, bmatrix, etc. of amsmath and mathtools. In these new environments, a TikZ node is created for each cell of the matrix. The user can use these nodes directly but nicematrix also provides commands which use these nodes to draw continuous dotted lines from two cells of the matrix (the result is more aesthetic than the classical result obtained using \cdots, \vdots, \ddots, etc.). This package also provides a control over the width of the columns and the possibility to add an exterior line and an exterior column. nicematrix requires and loads amsmath, array, expl3, l3keys2e, xparse, tikz, as well as the TikZ library fit.