Tired of paying expensive monthly subscriptions for clunky, slow billing software? Meet GST ProBill —a lightning-fast, highly secure, and feature-rich GST Billing and Inventory Management system built entirely on pure HTML, JavaScript, and Tailwind CSS.

Whether you want to run it 100% offline from your local browser, or connect it to Firebase for real-time Cloud Sync across multiple devices, GST ProBill gives you complete control over your business data without the recurring fees.

🚀 Why Choose GST ProBill?

Zero Server Setup: Runs directly in your browser. Just double-click the HTML file and start billing.

100% Privacy: Process your bills offline. Your financial data never leaves your device unless you choose to enable the optional Cloud Sync.

Developer Friendly: Clean, well-commented source code. Easily customize it, rebrand it, or integrate it into your own projects.

💼 Core Features:

•🧾 Advanced Invoicing: Generate professional Tax Invoices and Delivery Challans in seconds. Includes Auto-Round Off, Discounting, and automated CGST/SGST/IGST calculation based on customer state codes.

•🎨 3 Premium Print Themes: Choose between Classic (Blue), Modern (Green), or Boxed (B&W) invoice layouts with your custom Company Logo watermark.

•📈 Automated GST Reports: Instantly generate GSTR-1, GSTR-3B (B2B & B2C summaries), and HSN/SAC wise sales reports. Export them directly to Excel.

•📦 Smart Inventory Management: Features low-stock alerts, barcode scanner support, and Bulk Excel Upload for adding hundreds of items instantly.

•🏢 Multi-Company Support: Manage unlimited business profiles from a single dashboard.

•🔒 Built-In Security: Protect your data with an Admin PIN (full access) and Staff PIN (restricted to billing only).

•🔄 Smart Sync & Backup: Download your entire database as a JSON file, email it to yourself, or use the "Smart Merge" tool to sync data between your PC and mobile device.

🛠️ Tech Stack:

• Pure HTML5 & Vanilla JavaScript

• Tailwind CSS & DaisyUI (For a beautiful, responsive UI)

• SheetJS (For Excel Imports/Exports)

• Firebase Realtime Database (Optional, for Cloud Sync)

🎁 What You Get:

• The complete, unlocked index.html source code.

• Lifetime access to the tool.

• Freedom to use it for your personal business or modify it for your clients.