Compliance8 min read7 March 2026

GST Compliance for B2B Buyers: What Every Procurement Manager Must Know in 2026

Input tax credit, reverse charge mechanism, e-invoicing — GST adds complexity to every B2B purchase. Here's a practical checklist to stay compliant and avoid notices from the department.

GST is not optional for B2B. A non-compliant purchase can cost you 28% in denied ITC, plus interest and penalties.

The 3 things buyers get wrong most often:

1. Buying from unregistered suppliers If your supplier's turnover is above ₹40 lakh (₹20L for services), they must be GST registered. Buying from an unregistered supplier triggers Reverse Charge Mechanism — you pay GST on their behalf and can claim ITC, but the paperwork burden is yours.

VyaparSethu's GST Auto-fill verifies supplier GSTIN in real time before you finalize any deal.

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2. Accepting invoices without mandatory fields A GST invoice must include: Supplier GSTIN, Buyer GSTIN, HSN/SAC code, Tax rate (CGST/SGST or IGST), Place of supply. Missing any field means your ITC claim fails audit.

3. Not reconciling GSTR-2B monthly Your ITC eligibility depends on your supplier filing GSTR-1 correctly. If they don't file, you lose ITC even if you paid. Reconcile GSTR-2B vs. your purchase ledger every month before filing GSTR-3B.

E-invoicing threshold: ₹5 crore turnover If either party crosses this threshold, e-invoicing with IRN generation is mandatory. All invoices must go through the Invoice Registration Portal (IRP) before being sent to the buyer.

Checklist before paying any supplier invoice: - [ ] Supplier GSTIN verified and active - [ ] Invoice has IRN (if e-invoicing applies) - [ ] HSN/SAC code matches the goods/services - [ ] Place of supply matches delivery state - [ ] Invoice amount matches purchase order

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