Autoreply to Filtered Gmail Messages with Google Scripts

Published in: Gmail - Google Apps Script

This Google Script, originally published by @rboyd, scans for lengthy emails in your Gmail mailbox (messages that have more than 100 words) and sends an auto-reply requesting the sender to resend the email after editing to less than 100 words. The long email is archived (moved away from the Inbox) after the auto-reply has been sent. You can set it up as a trigger to auto-run every 15 minutes.

Also see: Email Auto-responder for Gmail

// Credit:

function deleteLongEmails() {

    var WORDLIMIT = 100;

    // Process only new emails in inbox that have not been read and receive in the last day
    var threads ="to:me is:unread in:inbox newer_than:1d");

    for (var i = 0; i < threads.length; i++) {

        // Ignore email conversations
        if (threads[i].getMessageCount() == 1) {

            var msg = threads[i].getMessages()[0];
            var word_count = msg.getPlainBody().split(' ').length;

            if (word_count > WORDLIMIT) {
                msg.reply("Your email is too long. Please resend after editing it to less than 100 words.");
📮  Subscribe to our Email Newsletter for Google tips and tutorials!
Published in: Gmail - Google Apps Script

Looking for something? Find here!

Meet the Author

Web Geek, Google Developer Expert
Amit Agarwal

Amit Agarwal is a Google Developer Expert in Google Workspace and Google Apps Script. He holds an engineering degree in Computer Science (I.I.T.) and is the first professional blogger in India. He is the developer of Mail Merge for Gmail and Document Studio. Read more on Lifehacker and YourStory

Get in touch

Google Add-ons

Do more with your Gmail and GSuite account

We build bespoke solutions that use the capabilities and the features of Google Workspace for automating business processes and driving work productivity.

  1. Mail Merge with Attachments
    Send personalized email to your Google Contact with a Google Sheet and Gmail
  2. Save Emails and Attachments
    Download email messages and file attachments from Gmail to your Google Drive
  3. Google Forms Email Notifications
    Send email notifications to multiple people when a new Google Form is submitted
  4. Document Studio
    Create beautiful pixel perfect documents merging data from Google Sheets and Google Forms
  5. Creator Studio for Google Slides
    Turn your Google Slides presentations into animated GIFs and videos for uploading to YouTube