GST reconciliation runs inside the GSTR-9 / 9C Working Paper, not as a separate task. Upload every quarter of GSTR-2A, every monthly 2B, every 3B and GSTR-1 return, CORAA merges them automatically and reconciles against books quarter by quarter, GSTIN by GSTIN. Matching now runs at document grain: credit notes and debit notes are matched as their own documents across both the GSTR-1 sales recon and the 2A/2B purchase-ITC recon, not netted into invoice totals before comparison, so a mismatched note doesn't hide inside a clean-looking invoice pair. The RCM tab reads the portal side too, cross-checking GSTR-3B Table 3.1(d) and the 2A/2B reverse-charge register against the books' own RCM flag on notified inward supplies. In one books-only engagement, this portal-side cross-check caught RCM liability understated by roughly 1000x, the books simply hadn't flagged the transactions; only reading the portal data surfaced it.
Two paths to the same audit conclusion. One leaves traces; the other doesn't.
Drop every GSTR-2A, 2B, 3B, and 1 file the client has produced, across every GSTIN. PDFs from the portal, JSON exports, Excel downloads, CORAA accepts all formats and merges them into one canonical view.
Books register is already loaded from the ERP ingest. CORAA matches every document, invoices, credit notes, and debit notes, across books and portal at document grain, runs bill-to-bill matching on the GSTR-1 side, verifies Rule 36(4) caps and Section 17(5) blocks, reconciles compensation cess, and cross-checks the books' RCM flag against GSTR-3B Table 3.1(d) and the 2A/2B reverse-charge register.
Open any variance to see the underlying document, the cause attribution, and the action options, accept, flag for client, or amend Form 3CD Clause 34 disclosure. RCM exposure and phantom-ITC flags from Rejected-in-IMS documents surface the same way.
Every document, invoice, credit note, or debit note, lands in one of three buckets: matched (clean tie), books-only (in your ledger but not on portal), or portal-only (on portal but not in books). Credit notes and debit notes are matched as their own documents instead of being netted into invoice totals first, and the GSTR-1 sales side also runs bill-to-bill matching.
The RCM tab cross-checks GSTR-3B Table 3.1(d) and the 2A/2B reverse-charge register against the books' own RCM flag on inward lines in notified categories, GTA, legal services, director sitting fees, security services, sponsorship, import of services. Reading the portal side surfaces Sec 9(3)/9(4) exposure with interest that a books-only read cannot see.
Per Rule 36(4), provisional ITC claimed under GSTR-3B cannot exceed eligible credit in GSTR-2B by more than the rounding tolerance. CORAA verifies this cap month by month and flags excess.
Identifies ITC claimed on blocked categories, motor vehicles, food and beverages, club memberships, staff welfare. Flags for review against the registered nature of business.
Compensation cess now runs through the ITC reconciliation alongside the tax-rate match, pair formation, cess summary, and ERP recognition, with a fix so ITC-ineligible cess is no longer wrongly flagged as an ordinary rate variance.
Documents the taxpayer rejected in the government's Invoice Management System are now captured and surfaced as a phantom-ITC risk flag, instead of silently disappearing from the reconciliation.
The GSTR-3B output reconciliation now sums across every GSTIN per month. Multi-registration entities used to silently lose all but one GSTIN from the output-tax total; every registration now counts.
GSTN portal exports come in many shapes, quarterly 2A PDFs, monthly 2B JSON, 3B summaries, GSTR-1 outward registers. CORAA accepts each format and merges into one canonical reconciliation. Every sync now carries its own per-tab, per-account staleness and error state, so a stale or errored fetch is never stored as if it were true data.
Beyond the return-to-return reconciliation, a set of standing checks flags risk that a pure tie-out misses: place-of-supply and HSN-rate mismatches, composition-scheme vendors billing tax they shouldn't, e-invoice applicability, GSTIN checksum validity, missing IRNs for taxpayers above the ₹5 Cr e-invoicing threshold, and ITC-at-risk on cancelled or suspended vendors under Section 16(2)(c).
