IMS and GSTR-2B Reconciliation Tool: Accept or Reject With the GRN in Hand

A GSTR-2B reconciliation tool matches the invoices your suppliers filed against your purchase register before you claim input tax credit (ITC). Since the Invoice Management System (IMS) went live in the October 2024 tax period, the tool must also support a decision on every invoice.

An AP Head or Financial Controller at a distributor with 600 supplier invoices a month usually stops at the match. The 2B line equals the register line, so the answer is Accept.

That proves the supplier filed and you booked the invoice. It does not prove the goods arrived, and Section 16(2)(b) of the CGST Act makes receipt of goods a condition of the credit.

This guide covers how IMS works, how to reconcile 2B with your register, and the check these tools rarely mention: the goods receipt note (GRN). KlearStack runs that check in its Supply Chain Document Compliance lane, through the AP Invoice Compliance AI Agent.

TL;DR

1. IMS has been live since the October 2024 tax period, and an ignored invoice is deemed accepted when GSTR-2B generates on the 14th.
2. A 2B-to-register match proves the supplier filed and you booked the invoice. It does not prove delivery.
3. Section 16(2)(b) of the CGST Act makes receipt of the goods a condition of ITC, and the GRN is the evidence.
4. Accept when the 2B line, register entry and GRN agree. Hold goods not yet received. Reject invoices that are not yours.
5. Large lists can go through the Excel-based IMS offline tool, with JSON in and JSON out.
6. The five-minute GRN-Less Credit Test counts the ITC in your 2B with no goods receipt behind it.
7. When comparing software, ask whether it reads the GRN, keeps the evidence, and leaves the final call with your team.

Run last month’s GSTR-2B against your goods receipts

What Is IMS in GST Return?

The Invoice Management System (IMS) is a GST portal facility for reviewing supplier invoices before they become your input tax credit. Records your suppliers save or file in GSTR-1, GSTR-1A or IFF appear on your IMS dashboard. You accept, reject or keep each one pending.

Per GSTN’s FAQs on IMS, your action decides where the invoice lands in GSTR-2B. Accepted records go to ITC Available and flow into GSTR-3B. Rejected records appear in a view-only ITC Rejected section, and pending records wait on the dashboard for a later month.

If you do nothing, the invoice is deemed accepted when GSTR-2B is generated on the 14th. For a Financial Controller, that default turns a quiet dashboard into a silent approval of every supplier’s filing. IMS therefore moves reconciliation from a month-end clean-up to a vendor reconciliation that starts the day a supplier saves an invoice.

Is IMS Mandatory, and From Which Month?

IMS has been live since the October 2024 tax period, and GSTN opened it for action from 14 October 2024. It is a facility, not a filing. GSTN’s advisory says records with no action are deemed accepted, so GSTR-2B still generates if nobody opens the dashboard.

The Council’s recommendation, published by PIB on 8 October 2026, is not a notified rule in the sources we checked. The portal advisory and FAQs we read set no date from which acting on every invoice becomes compulsory. The practical risk is the default, so ask top suppliers for a monthly supplier statement reconciliation and see a missing invoice before the 14th.

How to Reconcile GSTR-2B With Your Purchase Register

Download GSTR-2B for the month, load your purchase register, match each line on supplier GSTIN, invoice number and tax amount, then act on every difference. Repeat the match before you file GSTR-3B, because any action taken after the 14th requires you to recompute GSTR-2B.

1. Download GSTR-2B from the portal. GSTN’s GSTR-2B FAQs list Excel and JSON as the download formats.
2. Export your purchase register for the same period, with supplier GSTIN, invoice number, date and tax split.
3. Match on supplier GSTIN plus invoice number first, then on amount within the tolerance you set.
4. Sort the differences into four piles: in 2B only, in the register only, amount differs, and ITC not available in GSTR-2B.
5. For each pile, take the IMS action that fits and write the reason beside it.
6. Recompute GSTR-2B after any late action, then compare the ITC in 2B with the ITC you plan to claim in GSTR-3B.

The fourth pile needs care. GSTR-2B Table 4 lists credit you cannot take in Table 4(A) of GSTR-3B, such as invoices barred by the Section 16(4) time limit. GSTN adds that other provisions can still restrict credit, so you must self-assess. Blocked credit under Section 17(5) is the usual one, and it makes an invoice ITC not eligible.

What we see in AP teams at month end is that the register is built from invoices booked, not goods received. The 2B match then inherits whatever the booking step trusted. Purchase order reconciliation is where that trust first gets tested.

The 2B-GRN Gap: Invoices Filed for Goods You Never Received

The assumption is that a clean match means safe credit. The reality is that both sides of the match are built from invoices: the supplier filed one, and your AP team booked one. Neither shows the goods reaching your dock.

Section 16(2)(aa) of the CGST Act requires the supplier to furnish the invoice details and communicate them to you, which GSTR-2B shows. Section 16(2)(b) separately requires that you received the goods or services. A 2B line satisfies only the first, and both sit in Section 16 of the CGST Act.

The 2B-GRN gap is the ITC in your GSTR-2B for which you hold no goods receipt note. It is the distance between “the supplier says it supplied” and “your warehouse says it arrived”.

These rings sit on the supplier side, but your exposure is the credit you take on their invoices. In August 2025, DGGI Belagavi reported fake invoices of about Rs 145 crore from shell entities.

The GRN-Less Credit Test: Five Minutes on Last Month’s 2B

Every rupee of ITC in GSTR-2B should have a goods receipt behind it, and the rupees that do not are your 2B-GRN gap. Run this on last month’s file.

1. Open GSTR-2B and filter to ITC Available.
2. For each goods invoice, look up the GRN number in your ERP.
3. Total the ITC on invoices with no GRN. That total is your 2B-GRN gap.
4. Explain every rupee of it before the next 14th.

Illustration, with made-up figures: 36 of 600 invoices have no GRN, at Rs 14,000 of ITC each. The 2B-GRN gap is Rs 5.04 lakh.

KlearStack imports the downloaded GSTR-2B file and runs the goods-receipt check on the invoices in it. The AP Invoice Compliance AI Agent compares the invoiced quantity with the goods receipt and flags an invoice billed for goods not received. The exception goes to your AP approver with the evidence beside it, and the decision stays with your team.

A three-way match already tests invoice, PO and receipt for purchase-order buys. The 2B-GRN gap applies that discipline to the invoices the tax portal shows you.

A register match leaves an invoice reviewed. The GRN check makes it checked, and the logged decision makes it proven.

• Before: you know the supplier filed and you booked. Accept rests on two documents, and “prove receipt” means a hunt through the warehouse folder.
• After: you also know the goods arrived. Accept rests on three documents, and the GRN sits beside the 2B line.

See which 2B invoices have no goods receipt behind them

Accept, Reject or Pending: Decision Rules With Examples

Use three documents together. Accept when the 2B line, the register entry and the GRN agree. Hold or reject when any one of them does not.

The pattern across audit cycles is that invoices cleared in bulk in the first IMS month are usually the ones nobody matched.

Three examples show the rules at work.

• Truck still on the road: A Rs 2.4 lakh IGST invoice shows on the 12th, but the goods arrive on the 16th. Keep it Pending, post the GRN, then Accept.
• Quantity short: The invoice says 100 units and the GRN says 91. Keep it Pending and ask for an amendment or a credit note instead of accepting credit on 9 units you never received.
• Same invoice twice: A supplier re-files an invoice under a new number. Reject the second one, and run a duplicate invoice check before it is booked. An invoice from a supplier you cannot trace needs a fake invoice check first.

How to Act on More Than 500 Invoices in IMS (the Offline Tool)

On the portal you can select several records, or all of them, and apply one action to the selection. For large volumes, GSTN released an Excel-based IMS offline tool in April 2026. You download your IMS data as a JSON file, set actions in the tool, and upload the processed JSON back.

1. Download the IMS Offline Tool from the Downloads section of the GST portal, extract the zip file and enable macros in Excel.
2. On the IMS dashboard, open the Offline page and download your records as a JSON file.
3. Import that file into the tool, then set Accept, Reject, Pending or No Action against each record.
4. Click Validate Sheet, then generate the JSON file to upload.
5. Upload it on the same Offline page. If the portal returns a file marked “Processed with Error”, correct the rows and upload again.

These steps follow Taxmann’s report of the GSTN advisory. We found no record limit in it or in GSTN’s FAQs, so the 500 in the question is a quoted figure, not a rule. Check the portal before you plan batches.

If your register lives in SAP, invoice reconciliation in SAP shows how to get a clean export.

KlearStack takes the drudgery out of that sort. Invoices that fail the GRN check come back as exceptions with the evidence beside them, and the rest can go through in one bulk action. Your team keeps the judgment and presses the button.

Which Software Is Best for GST Reconciliation? (Evaluation Table)

The best GST reconciliation software passes four tests. It matches 2B to your register, supports IMS actions, checks the goods receipt, and keeps evidence an auditor can replay. The WhiteBooks, Tally and Coraa pages we read in October 2026 cover register matching, and none uses the term GRN.

Treat any GSTR-2B reconciliation software or IMS reconciliation software that cannot answer the third row as a matching tool, not a checking tool. For a wider shortlist, see the best invoice reconciliation software guide.

KlearStack is not a GST return-filing tool. It is the check layer beside your matching tool, and it shows which 2B invoices have goods behind them. A 30-minute pilot on last month’s documents needs only one month’s GSTR-2B and your GRNs, with nothing to install.

If you receive under 50 supplier invoices a month and one person signs every delivery, the spreadsheet version of the GRN-Less Credit Test is enough.

Claim Only the Credit You Can Prove

IMS made every supplier filing your decision. A match to the register answers whether the supplier filed. Only the GRN answers whether you received.

In October 2025, CGST Delhi South arrested a company director over about Rs 31.95 crore of ITC taken on invoices with no underlying supply. The cost of a missing GRN is not the interest. It is the credit, the notice, and the person who signed.

Start a pilot on one month’s GSTR-2B and GRNs

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