InvoicePro - NextJS 14 Invoice Billing System

InvoicePro is a production-ready, full-stack invoice and billing system built with Next.js 14 App Router, Prisma ORM, NextAuth.js, and Tailwind CSS.

It comes with a stunning dark premium UI, a real-time analytics dashboard, complete client management, payment recording, and a full REST API — everything you need to launch a professional billing platform for your business or clients.

The database uses SQLite by default (zero configuration, works immediately), but can be switched to PostgreSQL or MySQL with a single line change. Deploy to Vercel in minutes.

Built by a senior full-stack developer with 20+ years of enterprise software experience across fintech and government systems.

Features

• JWT Authentication — Secure login with NextAuth.js, bcrypt password hashing, protected routes
• Invoice Lifecycle — Draft → Sent → Paid / Overdue / Cancelled with one-click status updates
• Dynamic Line Items — Add unlimited items with quantity, unit price, and auto-calculated totals
• Tax & Discount — Percentage-based tax and discount with real-time summary preview
• Payment Recording — Log payments by Cash, Bank Transfer, Card, Cheque with balance tracking
• Client Management — Full CRUD for clients with company, email, phone, address, tax ID
• Analytics Dashboard — Revenue stats, 6-month chart, and invoice status breakdown
• REST API — 7 fully protected API routes with Zod validation
• Auto Invoice Numbers — Sequential numbering: INV-0001, INV-0002…
• TypeScript — Fully typed codebase throughout
• SQLite Default — Zero setup database, easily swap to PostgreSQL or MySQL
• Vercel Ready — Deploy to production in under 5 minutes
• Clean Dark UI — Premium dark theme with CSS variables, smooth animations
• Seed Script — Includes demo data with admin login for instant preview

Requirements

• Node.js 18 or higher
• npm or yarn package manager
• Basic knowledge of Next.js or React (for customization)
• No database server required — SQLite works out of the box
• Optional: PostgreSQL or MySQL for production deployments

Instructions

1. Unzip the downloaded file and open the folder in your terminal
2. Run npm install to install all dependencies
3. Copy .env.example to .env and set your NEXTAUTH_SECRET
4. Run npm run db:generate to generate the Prisma client
5. Run npm run db:push to create the database schema
6. Run npm run db:seed to load demo data
7. Run npm run dev and open http://localhost:3000
8. Login with admin@invoicepro.com / admin123

Full documentation is included in the README.md file inside the zip, including API reference, database switching guide, and Vercel deployment steps.