CODE EXAMPLE for those who use Google Apps Script…

Hope this helps others! Enjoy!

*Credit goes to the countless posters I piggy-backed off of to figure it out.

I call this function in a loop where ‘key’ is my super secret API key and everything else is pretty much spelled out. 🙂

function apiUpload(key, itemID, columnID, fileURL) {



  //GET THE GOOGLE DRIVE FILE ID FROM THE FILE URL TO GET THE FILE.

  var fileID = fileURL.match(/a-\\w]{25,}/);

  var file = DriveApp.getFileById(fileID);



  //YOU'LL PROBABLY NEED TO '.toString()' YOUR 'itemID' BEFORE IT GETS HERE.

  let query = "mutation ($file: File!) { add_file_to_column (file: $file, item_id: " + itemID + ", column_id: \\"" + columnID + "\\") { id } }";



  //BUILD THE MULTIPART REQUEST...

  //***NOTE (BECAUSE I'VE SEEN A LOT OF CONFUSION ABOUT THIS IN OTHER POSTS): THE "xxxxxxxxxx" IS LITERALLY WHAT I USE FOR 'boundary'. IT'S NOT A SECRET CODE OR ANYTHING. IT CAN PRETTY MUCH BE WHATEVER YOU WANT AS LONG AS IT DOESN'T APPEAR ANYWHERE ELSE IN THE BODY OF THE REQUEST. IT JUST ACTS AS A BOUNDARY SO THAT MONDAY KNOWS WHERE EACH CHUNK OF THE MULTIPART REQUEST TEXT (A.K.A. 'data') BEGINS AND ENDS.

  var data = "";

  var boundary = "xxxxxxxxxx";

  //QUERY PART

  data += "--" + boundary + "\\r\\n";

  data += "Content-Disposition: form-data; name=\\"query\\"; \\r\\n";

  data += "Content-Type:application/json\\r\\n\\r\\n";

  data += "\\r\\n" + query + "\\r\\n";

  //FILE PART

  data += "--" + boundary + "\\r\\n";

  data += "Content-Disposition: form-data; name=\\"variablesifile]\\"; filename=\\"" + file.getName() + "\\"\\r\\n";

  data += "Content-Type:application/octet-stream\\r\\n\\r\\n";



  //THIS IS HOW WE DO IT IN G.A.S.

  var payload = Utilities.newBlob(data).getBytes()

    .concat(file.getBlob().getBytes())

    .concat(Utilities.newBlob("\\r\\n--" + boundary + "--").getBytes());



  //FILE UPLOADS REQUIRE A DIFFERENT ENDPOINT THAN OTHER REQUESTS (ADD "/file").

  var url = "https://api.monday.com/v2/file";

  var options = {

    "method": "post",

    "headers": { "Content-Type": "multipart/form-data; boundary=" + boundary, "Authorization": key },

    "payload": payload

  };

  var response = UrlFetchApp.fetch(url, options);

  return response;

}