ZapBill

Create and send professional invoices in minutes — a complete SaaS solution for freelancers and agencies to manage payments, clients, and profits seamlessly

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🚀 Project Story: ZapBill – Smart Invoicing for Freelancers & Agencies

🌟 Inspiration

As freelancers ourselves, we were tired of manually building invoices, switching between tools, and constantly being asked to resend payment links. Most invoicing apps either lacked local payment options like UPI or were too complex for independent professionals.

We built ZapBill to empower freelancers and small agencies with a lightweight, powerful tool that makes invoicing fast, professional, and flexible.

💡 What it does

ZapBill helps users:

  • Create dynamic, professional invoices with unlimited line items
  • Add client details, custom taxes, and discounts
  • Accept payments via UPI, Bank Transfers, Crypto, or custom links
  • Download PDF invoices or send them via email (SMTP integrated)
  • Track invoice status: Paid, Unpaid, or Overdue
  • Manage their billing history with a beautiful dashboard

🔧 How we built it

  • Frontend: React + TailwindCSS for a fast, modern interface
  • Backend: Supabase (PostgreSQL + Auth + Realtime DB)
  • PDF Generator: pdfmake for flexible invoice templates
  • Email Sending: Hostinger SMTP (SSL via port 465)
  • Currency API: exchangerate.host for multi-currency support
  • Admin Panel: Custom dashboard to manage users, plans, invoices
  • Authentication: Supabase Auth with JWT session management

🧱 Challenges we ran into

  • Setting up real-time syncing with Supabase Realtime for admin controls
  • Designing a responsive and print-friendly PDF that looks good in email and download
  • Making invoice creation user-friendly but powerful for advanced use cases
  • Handling SMTP configuration securely and avoiding spam filters
  • Structuring user roles and access control for the admin vs users

🏆 Accomplishments that we're proud of

  • Built a complete end-to-end SaaS in a modular, scalable way
  • Integrated UPI, Crypto, and Bank payments – local-first payment support
  • Email delivery works reliably using Hostinger SMTP
  • Users can fully manage their profile, invoices, and plans in one place
  • Created a clean and customizable invoice layout that clients love

📚 What we learned

  • How to use Supabase to its full potential (Auth, Realtime, DB)
  • How to generate secure and branded PDFs using JavaScript
  • Handling email delivery issues like SPF, DKIM, and SMTP port challenges
  • Building scalable admin panels and role-based access logic
  • Importance of simplicity and performance in SaaS UI design

🚀 What's next for ZapBill

  • Adding Recurring Invoices for subscription clients
  • Launching Mobile PWA support for offline access
  • Introducing AI invoice assistant to auto-fill common fields
  • Enabling Client Portal for end-clients to view/download invoices
  • Launching on Product Hunt and offering affiliate rewards for referrals

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