R package heatmaply: Interactive Heat Maps Using ’plotly’. Create interactive heatmaps that are usable from the R console, in the ’RStudio’ viewer pane, in ’R Markdown’ documents, and in ’Shiny’ apps. Hover the mouse pointer over a cell to show details or drag a rectangle to zoom. A heatmap is a popular graphical method for visualizing high-dimensional data, in which a table of numbers are encoded as a grid of colored cells. The rows and columns of the matrix are ordered to highlight patterns and are often accompanied by dendrograms. Heatmaps are used in many fields for visualizing observations, correlations, missing values patterns, and more. Interactive heatmaps allow the inspection of specific value by hovering the mouse over a cell, as well as zooming into a region of the heatmap by dragging a rectangle around the relevant area. This work is based on the ’ggplot2’ and ’plotly.js’ engine. It produces similar heatmaps as ’d3heatmap’, with the advantage of speed (’plotly.js’ is able to handle larger size matrix), and the ability to zoom from the dendrogram panes.