Delete a bunch of emails (thousands) by tag from gmail

gmail-bulk-delete.js

function batchDelete() {
  var batchSize = 10; // Process up to 10 threads at once
  for (i = 175; i > 0; i--) {
    var threads = GmailApp.search('label:outbound older_than:' + i + 'd');
    for (j = 0; j < threads.length; j += batchSize) {
      GmailApp.moveThreadsToTrash(threads.slice(j, j+batchSize));
      // Logger.log('finished move %d', j);
    }
  }
}

currently not working for me because...

Cannot connect to Gmail (line 5, file "batch-delete")

works for me, had to authorize first

had a label with over 100,000 emails and no other solution worked, although the script times out after a few minutes it manages to delete a few thousand each time. I've slowly upped the batch size and so far that helps, haven't reached a batch size limit yet

function batchDelete() {
var batchSize = 100; // Process up to 10 threads at once
for (i = 175; i > 100; i--) {
var threads = GmailApp.search('label:outbound older_than:' + i + 'd');
for (j = 0; j < threads.length; j += batchSize) {
GmailApp.moveThreadsToTrash(threads.slice(j, j+batchSize));
//Logger.log('finished move %d', j);
}
}
}