Tally-Inspired Accounting SaaS Platform

I need a complete, production-ready accounting suite that feels as familiar and robust as Tally, yet runs as a modern web and mobile application so I can handle my own books and later license the service to other businesses.

Core scope
– All day-to-day accounting workflows you’d expect from Tally: voucher-style invoicing, double-entry ledgers, expense capture, bank reconciliation, and drill-down financial statements.
– Advanced modules switched on from day one: real-time inventory valuation, payroll with statutory deductions, and built-in GST/VAT compliance (return generation and e-filing hooks).
– Multi-tenant architecture with role-based access so I can onboard multiple client companies under a single cloud deployment and manage subscriptions.
– Two front ends: a responsive web app (React, Vue or similar) and companion mobile apps for Android and iOS built with a shared codebase (Flutter, React Native, or an equivalent framework).
– Central REST/GraphQL API, secure authentication (JWT/OAuth), and an admin console where I can configure features, pricing plans, and white-label branding.
– Data portability features: CSV/Excel import from Tally, one-click backup, and export to common formats for auditors.

Deliverables
1. Source code in a private repository, fully documented.
2. Staging server for acceptance testing plus deployment scripts for a scalable cloud stack (AWS, GCP, or Azure).
3. Mobile binaries ready for store submission.
4. User manual and API documentation.
5. Post-launch support window for bug fixes and knowledge transfer.

Acceptance criteria
• I can replicate a full Tally workflow (create a company, post vouchers, run a balance sheet) through the browser.
• Inventory, payroll, and GST functions operate without errors for at least three test companies.
• Web and mobile apps share the same live data and pass basic security tests (OWASP top 10).

If you already have a Tally-like engine or a SaaS framework that can be customized quickly, let me know; I’m open to proven shortcuts as long as ownership and licensing are clear.