IMS Perform Reconciliation matches the invoices in your purchase register (2P) with the invoices in IMS. You can run it for up to 30 GSTINs at once, and every request you place is listed in Get History, so you can follow its progress.

Submit a request

1. Open Reconciliation > IMS Based Purchase Recon > IMS Perform Reconciliation.
2. Select the GSTINs (maximum 30). Keep the section “All Other Types of Goods”, which covers B2B, B2BA, CDN and CDNA, that is, invoices, credit and debit notes and their amendments.
3. Choose a tab. Analyse Missing Invoices holds rules for invoices that did not match, and Analyse Mismatched Invoices holds tolerance rules for invoices that almost match. Tick the rules you want and select Submit. The rules are explained in the article “IMS: Advanced Reconciliation Rules”. If you tick no rule, only basic reconciliation runs.
4. Select Get History to follow your request. A banner reads “Reconciliation is in progress” until it finishes, and you can select Refresh to update it. When the request is complete, open IMS Recon Result to see the results.

What basic reconciliation does

Basic reconciliation always runs; it is not a checkbox that you need to tick. It pairs each invoice in your purchase register with the IMS invoice that has the same Counterparty GSTIN and Invoice Number. It then compares the remaining details, such as the invoice value, taxable value, tax amounts, place of supply, reverse charge and invoice type. Based on that comparison, each invoice is given a category: Match, Value Mismatch, Invoice Mismatch, IMS Only or Purchaser Only. The categories are described in the article “IMS: Reconciliation Categories”.

Which invoices are reconciled

IMS reconciliation does not re-run your whole purchase register. It works on the purchase invoices that matter for the open GSTR-2B period, and it picks its base automatically.

• Base: your GSTR-2B reconciliation if one exists for the financial year; otherwise your GSTR-2A reconciliation; otherwise neither.
• Included from the base: regular purchase invoices that are still N/A or Purchaser Only, plus invoices in the open period. The open period runs from the month after your last filed GSTR-3B to the current month. If GSTR-3B is already filed for the previous month, only the current month counts.
• With no 2B or 2A reconciliation: only purchase invoices in the open period are included.
• Left out: IMS invoices that were deleted or already force-linked.

For example, suppose you filed GSTR-3B for August and it is now October. The open period is September and October. A June invoice that is already matched in your 2B reconciliation is not included. A June invoice that is still unmatched is included. A September or October invoice is included whether or not it is matched.

In short, an older invoice that was already matched in your 2B reconciliation is not pulled into IMS reconciliation. Run or refresh your 2B or 2A reconciliation first, so that this works as you expect.

Why a GSTIN may be rejected

Before the request is submitted, the screen lists Invalid Requests and Valid Requests. Select Submit Valid Request to run only the valid GSTINs, and fix the others before trying again. A GSTIN is invalid if any of these apply:

• An IMS fetch, another reconciliation, or a save to GSTN is still running for it. Wait for it to finish.
• Its 2P data or IMS data is missing, and you see “Data Missing: Both IMS and purchase data is required for recon”. Upload your purchase register and fetch your IMS data.
• Your latest save to GSTN is newer than your latest IMS fetch, and you see “Save Date Exceeds Latest Get date”. Fetch your IMS data again, and then reconcile.