What to move first
Masters before transactions. Get these right and everything downstream inherits correctly.
- Customers, with GSTIN and state — the state drives CGST/SGST versus IGST
- Vendors, with GSTIN, so purchase credit reconciles
- Items, with HSN or SAC, unit and tax rate
- Opening stock quantities and rates
- Outstanding receivables and payables as opening balances
Pick a clean cut-off
Switch at the start of a quarter, or better, a financial year. A mid-period cut-off means one return drawn from two systems, which is exactly the reconciliation problem you are trying to leave behind.
Run the first month deliberately
Raise real invoices in the new system from day one rather than in parallel with the old one. Parallel running sounds cautious but produces two divergent sets of books. Check the first month's GSTR-1 summary line by line against your own records — after that, trust it.
Do not delete the old records
GST records must be retained for seventy-two months from the annual return due date. Archive the old system's exports somewhere durable before you decommission anything.
Common questions
Can I import my existing customer and item lists?+
Yes. Customers, vendors and items come across from a spreadsheet during setup, so you are not re-typing years of masters to get started.
What if my HSN codes are missing or wrong in the old data?+
Fix them during import rather than after. The code drives the rate on every future invoice, so a bad code propagates silently until reconciliation surfaces it months later.
Do I need an accountant to migrate?+
Not usually for the mechanics. It is worth having your CA confirm opening balances and the treatment of outstanding credit, since those carry forward into your first filed return.