The Metadata Compliance Checker (MCC) is an online tool and web service designed to check and validate the contents of netCDF and HDF granules for the Climate and Forecast (CF) and Attribute Convention for Dataset Discovery (ACDD) metadata conventions. It produces quantitative scoring for these convention attributes as HTML, PDF or JSON outputs. It also checks GHRSST version 2 data formats as applicable. It works with both user locally uploaded data as well as data that are accessible remotely via HTTP. The MCC is based on open source software originally developed by NOAA that has been extended with additional functionality and reporting.