Tally-Integrated Order & Distrbution Management App

I’m building a distribution-management application that talks directly to Tally Prime ERP so every sales order and payment stays perfectly in sync with our accounts.

Two user groups will work inside the same system.
• Internal staff need a dashboard where they can create, edit and track customer orders, then push the resulting invoices, receipts and ledger entries straight into Tally without manual export-import routines. Also check their regular tasks on the app assigned by their manager or owners.
• External customers will log in to place new orders, review their status and download invoices. Their activity must feed our Tally data in real time (or on a scheduled sync you recommend) so inventory and receivables remain accurate. They can view their accounts on phone, sales data on phone, pending dues. Also check updates on all running schemes

Key points to keep in mind
• Native, robust connection to the latest Tally APIs/ODBC; no brittle screen scraping.
• Clean role-based access so customers never see accounting numbers while staff can drill into them.
• Order lifecycle: placement → approval → dispatch → payment capture, with automated status updates to both user types.
• Accounting details—tax, discount, credit limits—should mirror the logic already configured inside Tally.

Stack, platform and timeline are flexible; I’m more interested in a solid, maintainable codebase than a rushed release. If you’ve built Tally integrations before, especially for distribution or FMCG, please mention it and outline how you would structure the sync layer and handle error reconciliation.