GST compliance for Indian businesses in FY 2026-27 is more demanding than ever. The Invoice Management System (IMS) is now mandatory. The 3-year filing cut-off has tightened. GST 2.0 simplified rate structure and the new e-invoicing threshold (Rs 5 crore) affect what most SMEs need to do every month.
Use this as a structured checklist of every recurring GST compliance obligation, organised by frequency.
Pre-Compliance Setup
Before you start the recurring cycle, confirm:
- GST registration is active. Check at gst.gov.in under Services > User Services > Search Taxpayer.
- GSTIN is correctly displayed on all invoices, bills of supply, debit notes, credit notes, and e-way bills.
- Authorised signatory details are current. Updates via REG-14.
- Bank account linked to GSTIN is active and matches your books for refund routing.
- Aadhaar authentication is complete for the proprietor or authorised signatory. Mandatory for new GSTINs and in many other cases.
- DSC (Digital Signature Certificate) is valid if your turnover requires DSC-based filing.
- Mobile and email in your GSTN profile receive notifications. Test by triggering OTP.
Monthly Compliance (Apply Every Month)
Outward Supplies (GSTR-1 / IFF)
- GSTR-1 for monthly filers (turnover above Rs 5 crore or who opted for monthly): file by 11th of the following month.
- IFF (Invoice Furnishing Facility) for QRMP filers: optional upload of B2B invoices by 13th of the following month for first two months of the quarter.
- Capture every invoice, credit note, debit note, advance receipt with correct rate, HSN code, and place of supply.
- Verify customer GSTIN before filing. Wrong GSTIN means the customer cannot claim ITC.
Inward Supplies and ITC (IMS + GSTR-2B)
- IMS workflow: log in to gst.gov.in, go to IMS dashboard. Review every supplier invoice flowing into your account.
- Accept correct invoices.
- Reject invoices that are not yours (wrong GSTIN attribution).
- Pending invoices where the supplier still needs to correct.
- After IMS actions, GSTR-2B is generated showing your eligible ITC.
- Cross-check GSTR-2B against your purchase ledger. Identify supplier-side errors and follow up.
Tax Payment and Summary Return (GSTR-3B)
- GSTR-3B for monthly filers: file by 20th of the following month.
- GSTR-3B for QRMP filers: file quarterly by 22nd or 24th of the month following the quarter (state-dependent).
- Verify auto-populated outward supplies from GSTR-1.
- Verify auto-populated ITC from GSTR-2B.
- Pay any net tax via cash ledger; ITC can offset outward tax.
- Reverse ITC on blocked credits, exempt supplies, and personal use as required.
- Critical: do not file with a mismatch between GSTR-1 and GSTR-3B outward supply totals; the system has a zero-mismatch policy from FY 2025-26 onwards.
TDS / TCS Returns
- GSTR-7 by 10th: if you are a GST TDS deductor (e.g., government or notified entity).
- GSTR-8 by 10th: if you are an e-commerce operator collecting TCS.
- GSTR-6 by 13th: if you are an Input Service Distributor.
E-Invoicing (Above Rs 5 Crore Turnover)
- If aggregate turnover in any previous year from FY 2017-18 onwards exceeded Rs 5 crore, e-invoicing is mandatory for B2B and B2G invoices.
- Generate IRN (Invoice Reference Number) on the IRP (Invoice Registration Portal) before issuing the invoice.
- Print the QR code on the physical or PDF invoice.
- Reconcile e-invoiced supplies with GSTR-1 monthly.
- If you are below Rs 5 crore turnover, e-invoicing is not mandatory but voluntary opt-in is allowed.
E-Way Bills
- Generate e-way bill for movement of goods above Rs 50,000 (some states have lower limits; check your state).
- For inter-state movement, generation is centralised on ewaybillgst.gov.in.
- Validity is one day per 200 km of distance; extend if delays occur.
Notice and Demand Tracking
- Daily: check GSTN dashboard for new notices (DRC-01, ASMT-10, REG-17, REG-18, etc.).
- Reply to every notice within the prescribed timeline (usually 7 to 30 days).
- Maintain a notice register with date received, reply due, status.
Quarterly Compliance
QRMP (Quarterly Return Monthly Payment)
For taxpayers below Rs 5 crore who have opted into QRMP:
- Monthly payment via PMT-06 by 25th of the following month (for first two months of the quarter).
- GSTR-3B quarterly by 22nd or 24th of the month following the quarter.
- GSTR-1 quarterly by 13th of the month following the quarter (in addition to optional monthly IFF).
TCS / TDS Returns
- Reconcile GSTR-7 / GSTR-8 with your records every quarter.
- Verify deductor / collector GSTINs against deduction certificates.
Annual Compliance
GSTR-9 (Annual Return)
For all regular taxpayers (turnover above Rs 2 crore are mandatory; below is optional but often done):
- GSTR-9 for FY 2025-26 due by December 31, 2026 (unless extended).
- Reconcile total outward supplies in GSTR-9 against books, GSTR-1, GSTR-3B, and audited financials.
- Reconcile total ITC claimed against GSTR-2B and books.
- Disclose adjustments, reversals, and any tax paid via DRC-03 during the year.
GSTR-9C (Reconciliation Statement)
For taxpayers above Rs 5 crore turnover:
- GSTR-9C filed alongside GSTR-9, due by December 31, 2026.
- Reconcile GSTR-9 against audited financial statements.
- Self-certify (no chartered accountant audit required since FY 2020-21).
Composition Scheme Annual Return
- GSTR-4 for composition taxpayers, due by April 30 of the year following FY end.
- FY 2025-26 GSTR-4 due April 30, 2026 (already past for prior year filers).
LUT for Exporters
- Letter of Undertaking for export of goods or services without payment of GST: file at the start of every financial year (April).
- Renewal is annual; without LUT, exports require IGST payment with refund claim.
Key Threshold Changes for FY 2026-27 to Watch
- E-invoicing threshold: Rs 5 crore aggregate turnover (in any year from FY 2017-18). Down from Rs 10 crore earlier.
- 3-year filing cut-off: From FY 2025-26, returns cannot be filed beyond 3 years from the relevant due date (subject to exceptions). Catch up on backlogs urgently.
- GST 2.0 rate structure: simplified slabs apply from April 1, 2026. Confirm new rates for your products and services.
- Aadhaar authentication for exporters and intermediaries: mandatory under GST 2.0.
- IMS becomes the gating workflow for ITC claims. Skip IMS actions and your ITC eligibility falls.
Common GST Errors That Trigger Notices
| Error | What Happens |
|---|---|
| GSTR-1 vs GSTR-3B turnover mismatch | DRC-01 demand notice; auto-blocked filing in some cases |
| ITC claimed but supplier did not file GSTR-1 | ITC reversal under Section 38 |
| Wrong HSN code on invoices above Rs 5 crore turnover | Penalty under Section 122 |
| Missed e-way bill on movement above limit | Detention of goods, 200% tax penalty |
| Reverse charge (RCM) not paid | Interest plus 100% penalty |
| GSTIN-wise turnover in ITR mismatches GSTR | Income tax notice under Section 143(1)(a) |
Quick Records to Maintain
- Sales register with GSTIN-wise summary
- Purchase register with supplier GSTIN, invoice date, ITC claimed
- E-way bill register
- E-invoice register (IRN generated)
- ITC register (eligible, ineligible, reversed)
- Cash ledger and credit ledger statements (download monthly from GSTN)
- Notice and reply register
Set Up a Monthly Workflow
- Day 1-5: consolidate sales and purchases for the just-ended month.
- Day 5-10: prepare GSTR-1; cross-check customer GSTINs; file by 11th.
- Day 11-14: review IMS and accept/reject inward invoices; generate GSTR-2B.
- Day 14-19: prepare GSTR-3B; reconcile against books; arrange tax payment.
- Day 20: file GSTR-3B.
- Throughout the month: monitor notices, generate e-invoices and e-way bills as transactions occur.
When You Need Professional Help
If any of these apply, get a managed GST compliance partner:
- Multi-state operations with multiple GSTINs
- E-commerce sales across marketplaces (Amazon, Flipkart, Blinkit)
- High ITC volumes (Rs 50 lakh plus monthly) where reconciliation errors compound
- Inverted duty structure or refund claims
- Recurring notices, ASMT-10s, or DRC-01s
- 12 months plus of pending returns
Tax Garden's GST compliance service handles monthly GSTR-1, GSTR-3B, IMS reconciliation, e-invoicing setup, e-way bill management, GSTR-9 / 9C, and notice replies. Pricing is flat upfront.
For deeper context, see our GST 2.0 simplified rate structure guide, IMS workflow changes, and Tax Compliance Calendar FY 2026-27.
Sources
This checklist is verified against the GSTN portal documentation (gst.gov.in), GST Council notifications, the CGST Act and Rules, the Invoice Management System (IMS) rollout circulars, the e-invoicing threshold notifications (CBIC notification reducing to Rs 5 crore), the GST 2.0 simplified rate structure announcements, and confirmatory coverage from ClearTax, IndiaFilings, Taxmann, and CBIC FAQs. Always confirm specific dates and thresholds against the official GSTN portal before filing.