What does AprilTax check before I file?

1. Filing setup - your filing period and type are consistent: IFF returns stay within their allowed tables, quarterly filing requires previous-FY turnover ≤ ₹5 Cr, and your turnover slab is declared.

2. GSTIN & invoice integrity - every recipient GSTIN has a valid 15-character format, and no B2B invoice number appears twice.

3. HSN classification - 9 checks: HSN present on every B2B line (and on B2C when turnover > ₹5 Cr), codes at least 4 digits (6 above ₹5 Cr), every code exists in the GST portal master list, service HSNs (99xx) carry UQC "NA" and qty 0, and the HSN sections the portal expects are actually in your JSON.

4. Tax arithmetic - intra-state CGST + SGST equals the IGST equivalent, Place-of-Supply on local sales matches your own state, and total GST stays within a sane share of sales (≤ 40%).

5. Documents issued - invoice series have no unexplained gaps, cancelled counts never exceed totals, cancellation rates look normal, and Table 13 is included.

6. E-commerce supplies (Table 14) - each marketplace appears once, tax signs match supply signs, and CGST equals SGST on intrastate rows.

7. TCS reconciliation - the GST portal's TCS statement matches your marketplace totals, and its operator GSTINs match Table 14.

8. Cross-table reconciliation - Table 12 taxable value and tax tie back to Tables 4-11, and Table 14 totals stay within Tables 4 + 5 + 7.

💡 Every check runs on every pass - you always get the complete report in one go, never one error at a time.