Before filing GSTR-1 and GSTR-3B, a Bangalore business should reconcile sales to GSTR-1, purchases to GSTR-2B/IMS, credit notes, reverse-charge items, prior-period corrections, e-invoice data and the cash/credit ledgers. The final tax preview should be approved before filing, and the ARN plus filed PDF should be retained. A return can be technically filed yet still be commercially wrong.
A correct return is a reconciliation, not a data-entry exercise
For most regular businesses, the reliable sequence is books first, portal data second and filing last. Your sales register should explain GSTR-1; GSTR-1 and permitted corrections should explain the outward-liability side of GSTR-3B; and the purchase register should be tested against GSTR-2B and IMS before ITC is claimed.
Use this checklist if your GSTIN files regular GSTR-1 and GSTR-3B
It is especially useful for Bangalore service companies, agencies, SaaS businesses, traders and growing SMEs with many invoices, credit notes or supplier mismatches. QRMP taxpayers should apply the same controls while respecting their quarterly return and monthly payment workflow.
Most GST mistakes start before the portal is opened
Typical causes are late sales invoices, e-invoice data not mapped back to books, credit notes posted in one system but not another, supplier invoices missing from 2B, unrecorded reverse-charge expenses, wrong place-of-supply treatment and prior-period corrections being forgotten.
Run the same sequence every month
1. Freeze the sales register. 2. Match taxable turnover to GSTR-1. 3. Check B2B GSTINs. 4. Check export/SEZ classification. 5. Reconcile e-invoice data where applicable. 6. Review credit/debit notes. 7. Review GSTR-1A/current correction opportunity. 8. Match purchase register to GSTR-2B. 9. Review IMS actions. 10. Identify RCM. 11. Reconcile electronic credit/cash/liability ledgers. 12. Approve the tax preview before filing.
| Check | Evidence | Red flag |
|---|---|---|
| Sales vs GSTR-1 | Sales register + portal draft | Unexplained turnover/tax difference |
| Purchases vs 2B | Purchase register + GSTR-2B | Claim without matching supplier record |
| IMS | IMS download/actions | Rejected/pending records not reviewed |
| RCM | Expense ledger | Foreign services/GTA/director or other RCM item missed |
| Tax preview | 3B draft + ledgers | No documented approval before filing |
Create a documented pre-filing pack
Download GSTR-1 data, GSTR-2B, IMS data where relevant, the electronic ledgers and your accounting extracts. Resolve material differences into buckets: timing, error, ineligible ITC, supplier action, amendment or additional liability. Only then prepare the return.
A ₹42 lakh sales month can still hide a return problem
Suppose the books show ₹42 lakh taxable sales, GSTR-1 draft shows ₹41.4 lakh and e-invoice data shows ₹42.1 lakh because one credit note was posted only in books and one invoice was duplicated on the IRP feed. Filing the draft without resolving both differences can create turnover mismatch and buyer-credit problems.
Small differences become notices, customer disputes or year-end clean-up
Persistent GSTR-1 versus GSTR-3B differences can trigger portal compliance communications. Unsupported ITC can create interest exposure. Missing or incorrect outward invoices can affect the customer’s GSTR-2B and payment relationship.
The client should know what is pending before anyone clicks File
TargoLegal’s review pack should identify the GSTIN and period, sales-versus-GSTR-1 difference, purchase-versus-2B/IMS difference, RCM, amendments, e-invoice exceptions, ledger position and proposed tax payment. The client approves the final summary; after filing, the filed return and ARN are retained.
What TargoLegal would ask for before filing or responding
The exact pack changes by issue, but these controls prevent the most common hand-off and accountability failures.
The proposed filing, payment, reversal, correction or response should be explained before submission. After filing, retain the ARN/filed PDF and any acknowledgement.
Do not make the problem harder to unwind
Reconcile books and source evidence before deciding tax treatment.
Use the exact period that created the mismatch, notice or filing obligation.
A correction should have a written bridge to the original error.
Save return PDFs, ARN, challans and the approved working.
What to send for a first review
Want a second review before your next Bangalore GST filing? Send the GSTIN, return period and approximate monthly invoice count on WhatsApp so the pre-filing scope can be identified.
Related questions
What should I send first?
Send the GSTIN, exact tax period and the document or mismatch that triggered the question. That usually determines the rest of the checklist.
Should I pay before reconciling?
Do not make a blind payment merely because a portal difference appears. Establish the legal and factual basis first, unless an undisputed liability is already clear.
Can the GST Portal data be wrong or incomplete?
Portal data is essential evidence but it still has to be reconciled with books, supplier/customer records and the applicable law.
What should I keep after filing?
Retain the filed return PDF, ARN, payment evidence, reconciliation working and any client-approved summary of adjustments.
When should I involve a GST professional?
Professional review is advisable where the issue affects material tax, ITC, notices, refund, registration status, exports, e-invoicing or multiple return periods.
Official sources used
Legal and portal claims on this page were anchored to the official sources below. Secondary discussions are not used as legal authority.
TargoLegal Research and Editorial Desk · Last legally reviewed: 18 August 2026. GST Portal workflows, notifications and due-date extensions should be rechecked immediately before action.
