Every month, around the 14th, a draft GSTR-2B lands on the GST portal. For most small businesses that draft is now shaped by one screen: the Invoice Management System (IMS). Each purchase invoice your suppliers upload sits there waiting for one of three answers from you: accept, reject, or keep pending. Whatever you choose decides how much input tax credit (ITC) shows up in your GSTR-3B.
This guide explains what each action does, which one to use when, and the mistakes we see most often when reviewing client books. It also clears up a rumour going around on WhatsApp about IMS becoming "mandatory" in 2026.
What is IMS in GST, in plain terms?
IMS is a dashboard on the GST portal that went live in October 2024. When a supplier reports an invoice, debit note or credit note in GSTR-1, GSTR-1A or IFF, that document appears in the buyer's IMS. The buyer can then accept it, reject it, or keep it pending.
Before IMS, your GSTR-2B simply showed whatever suppliers had uploaded. You had no say until you filed GSTR-3B. IMS moves that check earlier, so you can push back on a wrong invoice before the credit reaches your return.
What happens when you accept, reject or keep an invoice pending?
Your action | Effect on GSTR-2B | When to use it |
|---|---|---|
Accept | Counted as ITC available in this month's GSTR-2B | The goods or services were received, the amount and GSTIN are correct, and the credit is eligible |
Reject | Left out of available ITC; the supplier sees the rejection and can correct the document | Wrong amount, wrong GSTIN, duplicate, or an invoice you never received |
Pending | Kept out of this month's GSTR-2B and carried forward | Goods are still in transit, or you are waiting for the supplier to confirm a figure |
No action | Deemed accepted and counted in GSTR-2B | Never deliberately; this is what happens when nobody reviews IMS |
That last row matters most. Ignoring IMS is not neutral. A record you never open is treated as accepted, so a supplier's mistake flows straight into your credit, and the reversal (with interest) becomes your problem later.
A worked example: one month's IMS review
Say you run a hardware and plywood trading firm in Surat. On 12 November, your IMS for October shows 46 supplier documents. Your accountant matches them against the purchase register and finds:
41 invoices match on GSTIN, invoice number, taxable value and tax. These get accepted.
1 invoice from a laminate supplier shows ₹1,18,000 taxable value. Your purchase entry, and the physical bill, say ₹11,800. Someone added a zero. This gets rejected so the supplier can amend it.
1 invoice is a duplicate upload of an invoice already accepted last month. Rejected.
2 invoices are for a consignment that was dispatched on 30 October but reached your godown on 4 November. These are kept pending, because you can take credit only once the goods are received.
1 credit note from a supplier for a rate difference. You have not yet agreed the amount with them, so it stays pending (more on credit notes below).
If nobody had opened IMS that month, the ₹1,18,000 invoice alone would have pushed roughly ₹19,000 of excess ITC (at 18%) into GSTR-2B, ITC that would have to be reversed with interest once the mismatch surfaced.
How long can you keep an invoice pending?
Pending is useful, but it is not open-ended. Ordinary invoices can stay pending only until the time limit under Section 16(4) for claiming that credit. For FY 2025-26 invoices, that limit is 30 November 2026 or the date you file your annual return, whichever is earlier. After that, the pending option closes and you must accept or reject.
From the October 2025 tax period, GSTN also changed the rules for credit notes and certain downward amendments. These can now be kept pending, but only for one tax period: one month for monthly filers, one quarter for QRMP filers. GSTN added two related facilities at the same time:
When you accept a credit note, you can declare how much ITC you had actually claimed on the original invoice, so you reverse only that amount instead of the full credit note value.
You can add a remark when you reject or keep a record pending. The supplier sees it on their dashboard, which saves a phone call.
What does IMS not cover?
Some ITC never passes through IMS, so do not expect to see it there:
Reverse charge (RCM) purchases
Import of goods (ICEGATE records)
Documents from ISD (GSTR-6) and non-resident taxpayers (GSTR-5)
Documents where ITC is not available because of place-of-supply rules or the Section 16(4) time limit
Records where ITC must be reversed under Rule 37A
These still need to be tracked in your own books and reported correctly in GSTR-3B.
Is IMS mandatory in 2026?
You may have seen messages saying IMS became compulsory from April 2026 or July 2026. We have not found a notification, rule or GSTN advisory that says so. GSTN has described IMS as an optional facility, and GSTR-2B continues to be generated automatically on the 14th whether or not you act.
The practical answer is different from the legal one, though. Because records you ignore are deemed accepted, skipping IMS means accepting every supplier's figures without checking them. For any business with more than a handful of purchase invoices a month, reviewing IMS is the cheapest way to avoid blocked or reversed credit. If a new advisory does change the position, it will appear under News and Updates on gst.gov.in; check there rather than relying on forwards.
Don't forget to recompute GSTR-2B
This catches people every month. GSTR-2B is drafted on the 14th using the IMS actions taken by then. If you accept, reject or change anything after the 14th, the draft does not update by itself. You have to click Compute GSTR-2B again before filing GSTR-3B. Otherwise your return is built on the old draft. You can recompute as many times as you need until GSTR-3B is filed.
One more dependency: if last month's GSTR-3B is still unfiled, the next GSTR-2B draft will not be generated at all.
A simple monthly IMS routine
Keep the purchase register current. IMS review is only as good as the books you compare it with. Post purchase bills as they arrive, not at month end.
Review IMS before the 14th. Suppliers file GSTR-1 by the 11th, so most documents are visible by then.
Match on four fields: supplier GSTIN, invoice number, taxable value and tax amount.
Reject with a remark so the supplier knows exactly what to fix.
Use pending for timing, not for indecision. Note why each record is pending and when you will decide.
Recompute GSTR-2B if you changed anything after it was drafted, then file GSTR-3B.
Where hisabkitab fits in
The slow part of IMS is not clicking accept or reject. It is matching dozens of portal records against your purchase register to know which button to press. hisabkitab's GST module reconciles GSTR-2B against your books and flags mismatched values, wrong GSTINs and duplicate invoices, so you go into IMS already knowing which records need attention. We have written about how that matching works in AI-powered GST reconciliation and about catching GST errors before you file.
If you are a CA handling IMS for several clients each month, the CA plan lets you run the same review across all client companies from one login.
Frequently asked questions
What happens if I don't take any action on IMS?
Any record you leave untouched is deemed accepted and counted as available ITC in GSTR-2B. That includes incorrect or duplicate invoices, which you would then have to reverse later.
Can I change an action after accepting or rejecting an invoice?
Yes, until you file GSTR-3B for that period. After changing an action, recompute GSTR-2B so the return uses the updated figures.
Does rejecting an invoice increase my supplier's tax liability?
Rejecting an invoice does not by itself add to the supplier's liability. It tells the supplier the document is wrong so they can amend it through GSTR-1A or a later GSTR-1. A rejected credit note does add back to the supplier's liability in their next GSTR-3B.
When is GSTR-2B generated?
GSTR-2B is drafted automatically on the 14th of the following month. QRMP filers get it on the 14th of the month after the quarter ends.
Do RCM purchases appear in IMS?
No. Reverse charge records, imports and a few other categories bypass IMS. Track them in your books and report them directly in GSTR-3B.
Is IMS available for composition taxpayers?
IMS is built for taxpayers who claim ITC through GSTR-3B. Composition taxpayers cannot claim ITC, so IMS review is not part of their monthly routine.
Want to see how GSTR-2B reconciliation works on your own purchase data? Start a free trial or compare plans.
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