A free script that saves Gmail attachments to Google Drive

/**
 * Save Gmail attachments to Google Drive — a free Google Apps Script by Findest.
 * Guide: https://findest.site/archive/save-gmail-attachments-to-drive-script.html
 *
 * Copies every attachment that matches SEARCH into one Drive folder, renamed
 * with the date of the email, and labels each conversation once it is done so
 * it is never copied twice. Runs entirely inside your own Google account.
 */

// Settings — change these three lines.
const FOLDER_NAME = 'Gmail attachments';    // Drive folder, created if it does not exist
const SEARCH = 'has:attachment -in:chats';  // any Gmail search, e.g. 'from:supplier.com has:attachment'
const DONE_LABEL = 'saved-to-drive';        // added to each conversation once processed

const MIN_BYTES = 3 * 1024;  // skips signature images and tracking pixels
const BATCH = 50;            // conversations per run, so each run stays under the time limit

function saveAttachments() {
  const folder = getOrCreateFolder_(FOLDER_NAME);
  const label = GmailApp.getUserLabelByName(DONE_LABEL) || GmailApp.createLabel(DONE_LABEL);
  const threads = GmailApp.search(SEARCH + ' -label:' + DONE_LABEL, 0, BATCH);

  threads.forEach(function (thread) {
    thread.getMessages().forEach(function (message) {
      const day = Utilities.formatDate(message.getDate(), Session.getScriptTimeZone(), 'yyyy-MM-dd');
      message.getAttachments({ includeInlineImages: false }).forEach(function (file) {
        if (file.getSize() < MIN_BYTES) return;
        folder.createFile(file.copyBlob()).setName(day + '_' + file.getName());
      });
    });
    thread.addLabel(label);
  });

  Logger.log('Saved attachments from ' + threads.length + ' conversations.');
}

// Run this one once to make saveAttachments run by itself every hour.
function runEveryHour() {
  ScriptApp.newTrigger('saveAttachments').timeBased().everyHours(1).create();
}

function getOrCreateFolder_(name) {
  const folders = DriveApp.getFoldersByName(name);
  return folders.hasNext() ? folders.next() : DriveApp.createFolder(name);
}