You can also call this utility from the command line. For example, using curl to upload a file "file.xls":
curl -F "[email protected]" https://apps.jansson.net/dataupload/
To upload two (or more) files, use the array syntax like in PHP:
curl -F "f[][email protected]" -F "f[][email protected]" https://apps.jansson.net/dataupload/