How I Built DueBook – A Vendor Payment Planner

July 12, 2025 • Saheef

DueBook is a smart financial planning tool designed to simplify vendor payments for small businesses. It helps you visualize upcoming dues, schedule payouts, and avoid payment stacking. With built-in logic for due dates and a flexible calendar interface, it turns manual ledger juggling into a smooth drag-and-drop experience. Everything works offline and feels like a native app.

💡 Key Features

🧠 How It Works

DueBook allows you to add vendors along with a nickname, legal name, payment amount, terms (like Net 7, Net 15), and priority. Based on the input date and terms, it auto-generates a due date and drops it on the calendar. From there, you can drag and reschedule with full control.

// Auto-calculate due date based on terms
function calculateDueDate(startDate, termDays) {
  const base = new Date(startDate);
  base.setDate(base.getDate() + termDays);
  return base.toISOString().split('T')[0];
}

The calendar is fully interactive. Payments are stacked by date and color-coded based on priority. You also get alerts if too many payments fall on the same day.

📊 Dashboard & Alerts

The dashboard shows a summary of upcoming payouts and total due amounts. A red dot warns when payment stacking occurs. AI logic will soon suggest alternative dates for balancing your cash flow without missing deadlines.

📁 Export & Portability

DueBook lets you export your vendor payment calendar as CSV or PDF. This means you can share it with finance teams or import it into external tools. All vendor data and schedule are stored in localStorage so they persist offline.

📱 Progressive Web App

DueBook is installable like an app and works fully offline using a service worker. You can use it on mobile or desktop and manage your payments on the go.

"I wanted to build something that felt powerful yet personal. DueBook became a lightweight financial ally — not just another spreadsheet." – Saheef
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🔮 What's Next?