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Validation checks

A check says my HSN code is "not in the GST master list" - how do I fix it?

  1. The GST portal only accepts HSN/SAC codes from its official master list - an unknown code triggers an "invoice level error" at filing. AprilTax catches it first.

  2. Open Review HSN Code - every invalid row is flagged red at the top of the table.

  3. Rows with an auto-suggestion have a one-click Use button - accept it. For rows without one, search by HSN code or product name and pick the right code.

  4. Click Save, regenerate the return, then Re-run checks.

💡 A code can be "technically valid" but still rejected - the portal refuses 2-digit codes, and B2B lines need at least 4 digits (6 above ₹5 Cr turnover).

More in Validation checks

? What does AprilTax check before I file?
All 30 checks, grouped - HSN, tax arithmetic, documents, e-commerce, reconciliation. › ? A validation check failed - what happens now?
Critical vs advisory findings, and the fix → re-run loop. › ? Why am I asked to set my turnover slab?
The ₹5 Cr slab decides your HSN rules - filing can't proceed without it. › ? Table 12 doesn't match my sales totals - what do I do?
HSN summary vs Tables 4-11 mismatch - usually fixed by regenerating. › ? A marketplace row shows negative sales or the wrong tax sign - is that a problem?
Negative net supply is usually fine; an opposite-sign tax needs a fix. › ? A check flags "gaps in my invoice series" - should I worry?
Usually cancelled or unused numbers - advisory only, filing isn't blocked. › ? "HSN code must be present on every B2B invoice line" - how do I fix it?
B2B lines always need an HSN of at least 4 digits - fill them in the HSN review table. › ? My turnover is over ₹5 Cr - what extra HSN checks apply?
6-digit codes everywhere, B2C included, and both HSN sections in the JSON. › ? "TCS statement differs from uploaded sales" - what do I do?
The portal's TCS statement and your files disagree - review it in the TCS Match step. › ? "TCS statement operators appear in Table 14" flagged an operator - why?
An operator on your TCS statement is missing from Table 14, or listed under the wrong GSTIN. › ? "GSTIN format invalid" - my own, or a buyer's. How do I fix each?
A GSTIN that isn't 15 valid characters gets rejected at the portal - here's both fixes. › ? Other validation flags, decoded - quick reference
The occasional checks: cancellation rate, GST over 40%, duplicate operators, POS mismatch. ›
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