Graphtage is a command-line utility and underlying library for semantically comparing and merging tree-like structures, such as JSON, XML, HTML, YAML, plist, and CSS files. Its name is a portmanteau of “graph” and “graftage”—the latter being the horticultural practice of joining two trees together such that they grow as one. Graphtage performs an analysis on an intermediate representation of the trees that is divorced from the filetypes of the input files. This means, for example, that you can diff a JSON file against a YAML file. Also, the output format can be different from the input format(s). By default, Graphtage will format the output diff in the same file format as the first input file. But one could, for example, diff two JSON files and format the output in YAML. There are several command-line arguments to specify these transformations; please check the --help output for more information.