The bulk data API gives users with permission to access the premium web services access to full data set downloads in a compressed CSV format. Entire classification-years may be downloaded. Reporter-classification-years may be accessed as well. Since the files have been already been generated this API provides a much faster interface to access large amounts of data. There are two main access points, one for bulk file availability and the other to download the bulk files.
For more details, please refer to: http://comtrade.un.org/data/doc/api/bulk/
Note: At this time, this feature is only available to premium site license subscribers. As an alternative, please try out our public Data API: http://comtrade.un.org/data/doc/api/