Tally Solutions
Software Development Engineer I & II
Overview
Tally Solutions is one of India's most widely used business software products, with over 7 million active businesses. I worked on the core Tally Prime product as a Software Engineer — contributing to the accounting engine, building statutory compliance modules for the GST era, and helping architect the REST API layer that enabled third-party integrations.
The Challenge
Tally Prime was undergoing a major re-architecture during my tenure — transitioning from TDL (Tally Definition Language) monolith to a hybrid model with a modern REST API layer. The challenge was maintaining full backward compatibility with 10+ years of customer data and configurations while modernising the integration layer and keeping up with quarterly GST regulation changes from the Indian government.
What I Built
Developed GSTR-9 (Annual Return) and GSTR-9C (Reconciliation Statement) compliance modules in TDL and C++ — handling complex tax computation across 30+ GSTIN registration types with support for amendments, credit notes, and debit notes.
Contributed to the Tally REST API layer: designed and implemented 15+ endpoints for voucher creation, ledger queries, balance sheet extraction, and report generation — used by 200+ certified third-party integration partners.
Built an automated regression test suite using Python + Selenium that replayed 10,000 real customer transaction sequences against each release, catching compliance regressions before they shipped to 7M users.
Implemented the e-Invoice API integration (IRP/NIC portal) — digital signing of B2B invoices, QR code generation, IRN (Invoice Reference Number) management, and error reconciliation for failed submissions.
Optimised the ledger summary computation for large datasets: companies with 500K+ vouchers/year were taking 45+ seconds to generate a P&L report. Rewrote the computation using incremental aggregation with a dirty-flag cache, reducing it to under 3 seconds.
Tech Stack
Core
Testing & Tooling
Compliance