A clear dashboard
Total due, active contracts, this month’s collections and the number overdue, with a button for recording a quick payment.
All work
Built for a phone shop
Installments management system
An installments system for a phone shop: customers, contracts and payments in one place, with overdue tracking and automatic WhatsApp reminders.
About the project
An installments system for a phone shop: customers, contracts, payments and outstanding balances in one place, with follow-up on anyone who falls behind.
Its core is the reminders: the system sends every customer an automatic WhatsApp reminder before their installment is due, and spreads the messages across the month so the daily sending cap is never exceeded.
The screens on this page use demo data.
Highlights
Reminders spread across the month
The system spreads contracts across the days of the month within a daily cap, so every reminder arrives on time without breaching sending limits.
WhatsApp message log
Every message’s status is visible; failed sends are logged and retried automatically on the next run.
Settings in the owner’s hands
Shop name, how many days before the due date to remind, retry days and the daily message cap.
How it’s built
Technology
- React
- TypeScript
- Vite
- Tailwind CSS
- Supabase
- PostgreSQL
- pg_cron
- Deno
- WhatsApp Cloud API
- No backend server: the dashboard talks to the database directly, and every table is protected by its own permission policies.
- A scheduled job runs every day at 9 a.m. Baghdad time and triggers a function that sends the reminders through the WhatsApp Cloud API.
- Every reminder is claimed before it is sent, so no customer gets the same message twice.
- Due days run from 1 to 28, so month-end contracts never pile up on one day in February.
- If a send fails or the cap is reached, it retries on the due day and the two days after, then stops.
- 138 automated checks build a temporary database and verify all of the logic, without sending a single message.
Have a similar idea?
Tell us about it, and we’ll work out the scope, the detail and the cost together.