Explanation
Before entering a vendor in your purchase register, verify their GSTIN on the GST portal (gst.gov.in → Search Taxpayer). Check: (1) Registration status: Active vs Cancelled vs Suspended. (2) Return filing status: look for gaps in GSTR-1/3B filing history. (3) GSTIN structure: must be 15 characters — 2-digit state code, 10-char PAN, 1-digit entity number, 1 alpha check-digit, 'Z', 1 checksum. A cancelled GSTIN means their invoices cannot generate valid ITC for you. A suspended GSTIN is a red flag. Due diligence — verify before claiming ITC. Verify on the GST portal before filing.