I need a custom billing solution that works like Vyapar but is tailored to my workflow. The core of the project is straightforward: create an intuitive invoicing system that handles inventory management, performs accurate GST calculations on every transaction, and supports multiple user access so my team can work simultaneously without hiccups. Beyond the billing engine itself, I want the software to sit comfortably in my current tech stack. It must exchange data seamlessly with my accounting software, feed customer information to my CRM, and process payments through popular gateways. If you have ready-made connectors, great—otherwise we’ll map out the APIs together. What I expect from you: • An installable, production-ready application with clean UI/UX. • Inventory, GST, and multi-user modules fully tested. • Stable integrations with the accounting package, CRM, and at least one mainstream payment gateway. • Source code, build instructions, and brief user documentation. If you have experience building GST-compliant billing tools for the Indian market—or have already tackled Vyapar-style projects—let’s discuss timelines and milestones.