Reminder System
An intelligent, multi-stage reminder automation that follows up on unpaid balances via Email and WhatsApp and generates real-time defaulter reports.
Problem Statement
The Solution
Automation Overview
We built a fully automated reminder system that reads payment records from a Google Sheet, evaluates due dates, and sends the right reminder at the right time using Email and WhatsApp. The system also generates a clean defaulter list for admins, giving full visibility without manual tracking.
Central Payment Tracker (Google Sheets)
A Google Sheet acts as the single source of truth, storing customer name, contact details, amount due, due date, payment status, and last reminder sent. This keeps everything simple and transparent.
Intelligent Due-Date Evaluation
The workflow runs on a schedule and checks each unpaid record to calculate how overdue it is. Based on this, each record is automatically categorized as Gentle Reminder (Just past due), Firm Reminder (Significantly overdue), or Urgent Reminder (Critical delay). No hard-coding. Everything adjusts dynamically based on dates.
Multi-Stage Reminder Logic
Each reminder stage has its own message tone, copy style, and escalation level. Early reminders stay polite and friendly. Later reminders become firm and urgent — without sounding unprofessional. This mirrors how a human would follow up, but runs automatically.
Email + WhatsApp Delivery
For every reminder, an Email is sent for formal documentation and a WhatsApp message is sent for faster visibility. This ensures reminders are actually seen, not ignored in inboxes.
Duplicate & Spam Protection
The system tracks when the last reminder was sent and which stage has already been triggered. This prevents sending the same reminder repeatedly, spamming clients, or escalating too quickly. Every reminder is intentional and controlled.
Automatic Defaulter List Generation
The workflow compiles a real-time defaulter report that includes overdue customers, number of days overdue, reminder stage reached, and outstanding amounts. This report is sent directly to administrators for quick review and action.
Clean Error Handling
If contact details are missing or invalid, the system skips safely, logs the issue, and includes the record in the admin report. No silent failures.
Integrations & Connected Systems
Google Sheets – payment records & logic source; Email service – formal reminder delivery; WhatsApp API – instant notifications; n8n – scheduling, date logic, message routing.
Smart Logic & Reliability
- Date-based escalation logic
- Safe reminder spacing
- Stage tracking per record
- Admin-only reporting
- Scales easily across hundreds or thousands of records
Before
Manual checking, forgotten follow-ups, awkward calls, inconsistent reminders.
After
Automated, polite, structured follow-ups with full visibility — without lifting a finger.
Tools Used
Our Process
Discover
Identified inefficiencies in manual payment tracking.
Design
Created a multi-stage escalation model.
Build
Automated date evaluation and messaging logic.
Integrate
Connected Email, WhatsApp, and Sheets seamlessly.
Deploy
Tuned reminder timing and tone.
Business Impact
Faster payment collection
Reduced manual follow-ups
Professional, consistent communication
Clear visibility into defaulters
Less stress for finance teams
Fully automated daily operations
"This Reminder System replaces manual payment chasing with an intelligent, automated follow-up engine. By combining date-based logic, multi-channel messaging, and real-time defaulter reporting, businesses can collect payments faster — without friction or human effort."
Want a system like this for your business?
Let’s build it.