GST Reconciliation Across 15 GSTINs and 20 Branches — Without 20 Tally Logins
A client with operations in 15 states doesn't have one GST reconciliation problem — it has 15 of them, each with its own GSTIN, its own filing cadence, its own Tally company file, and its own set of portal exports. The mechanical burden of just assembling that data before reconciliation can start is often bigger than the reconciliation itself. One firm described managing a client with multiple GST numbers as requiring a different Tally login for each registration — and that's before a single line of GSTR-2A gets compared to the books.
Why multi-GSTIN clients break the standard reconciliation workflow
The standard GST reconciliation workflow assumes one entity, one GSTIN, one set of returns. The moment a client has multiple registrations — branches in different states, or a large single-state operation split across registrations for other reasons — that assumption stops holding. Books vs. GSTR-2A/2B/3B reconciliation has to happen per-GSTIN, but the output-tax picture (what the entity owes in total) only makes sense summed across every registration. Get the consolidation step wrong — miss a secondary registration, double-count a branch — and the total is wrong even if every individual GSTIN's reconciliation was done correctly.
What consolidated reconciliation actually looks like
The workable approach doesn't require 15 separate reconciliation runs stitched together by hand afterward. CORAA's GST reconciliation accepts every GSTR-2A, 2B, 3B, and 1 file a client has produced — PDFs from the portal, JSON exports, Excel downloads, whatever format each registration happens to be in — across every GSTIN, and merges them into one canonical view. The GSTR-3B output-tax reconciliation specifically sums across every GSTIN per month, so a multi-registration entity doesn't silently lose a secondary registration's liability out of the total the way manual consolidation often does when a branch's return gets forgotten in the shuffle.
Underneath the consolidated view, each GSTIN still gets its own proper reconciliation — Rule 36(4) ITC-cap testing, Section 17(5) blocked-credit detection (a separate check from the Rule 36(4) cap: 17(5) flags credit claimed on categories the law blocks outright, like motor vehicles or staff welfare, regardless of whether the 2B supports the amount), and GST health checks covering place-of-supply mismatches, e-invoice applicability above the ₹5 Cr AATO threshold, and ITC-at-risk on cancelled or suspended vendors under Sec 16(2)(c).
The OTP problem nobody wants to say out loud
There's a friction point that comes up almost as often as the multi-GSTIN complexity itself: pulling data directly from the GST portal typically means a live, OTP-gated session — which means either the client shares portal credentials (a real trust and security concern most clients are reasonably reluctant about) or the auditor waits on the client to be available to authorize each pull. Firms have asked directly whether reconciliation is even possible without it.
It is, and it's arguably the better design regardless of the friction: reconciliation works from the exports the client or their GST practitioner already has — the PDFs, JSON, and Excel downloads every GSTIN-holder routinely pulls for their own filing — rather than requiring a live, credential-based session against the portal. Nobody has to hand over portal access, and the auditor isn't blocked waiting on a client's availability to authorize a pull.
What to check before committing to a tool for a multi-entity client
If your practice includes clients with multiple GSTINs or branches, the questions worth asking any vendor before you commit: does the tool genuinely consolidate across registrations into one output-tax total, or does it just process each GSTIN separately and leave the summing to you? Does it require live portal access, or can it work from exports? And does it distinguish between Rule 36(4)'s ITC cap and Section 17(5)'s blocked-credit test — two different checks that get conflated more often than they should be, given how differently they behave on the same claimed ITC.
Frequently Asked Questions
Can GST reconciliation be done without the client sharing their GST portal login?
Yes — reconciliation can run entirely from the exports a client or their GST practitioner already has (2A/2B/3B/1 as PDF, JSON, or Excel), without needing a live, OTP-gated portal session.
How is Section 17(5) different from the Rule 36(4) ITC cap check?
Rule 36(4) tests whether claimed ITC stays within the portion supported by GSTR-2B. Section 17(5) is a separate test that flags ITC claimed on categories the law blocks outright — motor vehicles, food and beverages, club memberships, staff welfare — regardless of whether the 2B supports the amount. A claim can pass the Rule 36(4) cap and still fail the Section 17(5) test.
Does the output-tax reconciliation actually sum across all of a client's GSTINs?
It should — the GSTR-3B output-tax reconciliation needs to sum across every GSTIN per month for a multi-registration entity, otherwise a secondary registration's liability can go missing from the total even when each individual GSTIN's reconciliation is correct.
What GST checks matter beyond the basic books-vs-return reconciliation?
Place-of-supply and HSN-rate mismatches, composition-scheme vendors billing tax they shouldn't, e-invoice applicability above the ₹5 Cr AATO threshold with missing IRNs, GSTIN checksum validity, and ITC-at-risk on cancelled or suspended vendors under Sec 16(2)(c) — a pure return-to-return tie-out misses all of these.
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