Sheet Follow-Up Mailer

Gmail follow-ups from a Google Sheet that stop automatically when someone replies.

Put your contacts in a sheet and write 2 to 5 short emails. The script sends step 1, then each follow-up after the number of days you choose, as a reply in the same Gmail thread. When someone replies (or the address bounces), their row is marked and they get nothing more. It runs as an Apps Script in your own Google account, so there's no monthly tool and no third-party server.

What's inside

• Code.gs: one file to paste into Extensions → Apps Script. It adds a "Follow-Up Mailer" menu to your sheet.
• Auto-created tabs: Contacts, Sequence, Settings and Log
• Placeholders such as {{FirstName}}, {{Company}} or any column header
• Dry-run mode (on by default) that logs what would be sent without sending
• A daily send limit, a send-hours window, an option to skip weekends and a "send test to me" button
• Reply and bounce detection on each thread, plus Paused/Unsubscribed rows you can set by hand
• Hourly auto-run trigger that you can switch on and off from the menu
• A step-by-step setup README (about 10 minutes) and CSV templates
• A Node test harness with 13 tests against fake Gmail/Sheets objects

Screenshots

The test suite run:

A local simulation of the sheet after three contacts (one replied, one bounced, one finished the sequence). This was rendered from the test harness, not from a live Google account:

Good fit for

• Following up on quotes, proposals, invoices, job applications or partnership emails
• Small lists where you'd otherwise send "just bumping this" by hand

Honest limits

• Gmail's own daily sending limits apply (about 100 recipients a day on free Gmail, more on Workspace). This is not a bulk or cold-blast tool.
• Out-of-office auto-replies count as replies and stop the sequence.
• A reply sent as a brand-new email, outside the thread, isn't detected. Mark that row "Replied" by hand.
• Plain-text emails only. There are no attachments, HTML templates or open/click tracking.
• The logic was tested in a local harness that fakes Gmail and Sheets, not on a live Google account. Start with dry run and a small list. Google may change Apps Script quotas or behaviour.
• No promises about results. It sends your emails on schedule, and what they say is up to you. You're responsible for following anti-spam law.

Buy

$19 USDT. DM @shivaprasa41203 on X. The zip is delivered after payment, and bug fixes are free for buyers.