Run win-back drip email campaigns with Google Sheets and SMTP

Description

Quick Overview
This workflow runs daily and weekly to manage a win-back email drip from a Google Sheets tracker, sending staged reactivation emails via SMTP after a compliance sub-workflow approves them, then updating the tracker and emailing a weekly status summary to the firm.

How it works
Runs every morning at 9am and reads the “Win-Back Tracker” data from Google Sheets.
Calculates which active leads are due for the next drip stage based on days since marked_cold_at and the configured WIN_BACK_DRIP_STAGES sequence.
Builds a personalized, stage-specific win-back email (subject, text, and HTML) using the lead’s name and practice area.
Sends the email content to a separate compliance/guardrail workflow and checks whether the message is approved or the recipient has opted out.
If approved, sends the drip email via SMTP and updates Google Sheets with last_stage_sent and last_sent_at for the matching lead_id.
Runs every Monday at 8am, summarizes active/reactivated/unsubscribed counts from Google Sheets, and sends the weekly summary email to the firm via SMTP.

Setup
Connect Google Sheets credentials and set WIN_BACK_TRACKER_SHEET_ID to the spreadsheet that contains a “Win-Back Tracker” sheet with fields like lead_id, email, status, marked_cold_at, and last_stage_sent.
Configure an SMTP email credential and set FIRM_FROM_EMAIL (sender) and FIRM_EMAIL (weekly summary recipient).
Create or select a compliance/guardrail sub-workflow, set GUARDRAIL_WORKFLOW_ID, and ensure it returns an approved boolean (and handles opt-outs) for the provided email content.
Set WIN_BACK_DRIP_STAGES (for example 0|check-in;14|resources;30|last-call) and adjust the stage email copy in the drip email template code if needed.
Confirm the schedule trigger times (daily 9am and Monday 8am) match your timezone and operating hours.