GSTR-1 Due Today: A 45-Minute Sprint Checklist for Tally + GSTN Mismatches

GSTR-1 for June 2025 is due today, July 11. It is 9:18 am IST and we have already finished filings for 7 of 14 clients on this morning's sprint. The other 7 have one of four mismatch patterns blocking the upload — and these are the same four patterns we caught last cycle. This post is the exact 45-minute Tally Prime to GSTN sprint we run, the four mismatch types, and the fix flow for each. If you are reading this before 5 pm, you can still file clean today. ## The answer in 60 words Export GSTR-1 JSON from Tally Prime (Display More Reports > Statutory > GSTR-1). Cross-check B2B invoice values against your IRN log, NOT against ledgers. Validate HSN summary in Table 12 using the dropdown selector. Upload JSON to [gst.gov.in](https://gst.gov.in/), fix portal validation errors, file with EVC or DSC. The four mistakes most SMBs make: missing IRNs, wrong place-of-supply, HSN code drift, B2C cap miscount. ## Why today's deadline matters The July 2025 tax period (filed in August) is the first cycle under the [hard-locked GSTR-3B Tables 3.1 and 3.2](https://cleartax.in/s/hard-locking-in-gstr-3b). Today's GSTR-1 for June is the LAST cycle where you can edit GSTR-3B Table 3 values during filing. Get into the habit now — wrong GSTR-1 = wrong GSTR-3B with no edit room from August onward. The bigger headache for SMBs: GSTR-1 errors filed today get inherited by your buyer's GSTR-2B next week. If you mis-key a buyer's GSTIN, that buyer's ITC claim fails. Three of our clients caught notices from buyer-side accounts teams over the May cycle. The cost of one wrong digit in a GSTIN: a six-week reconciliation loop, often with the buyer holding payment. ## The 4 mismatch patterns we catch every cycle ## The 45-minute sprint (run this between 10 am and 4 pm today) ## What breaks at the portal (real errors from this morning)

Portal error	Root cause	Fix
"Invalid GSTIN"	15-char GSTIN with wrong check digit (typo in buyer master)	Verify GSTIN at GSTN Search Taxpayer. Update Tally party master. Re-export.
"HSN code not found in master"	Manual HSN override that bypassed the master list	Use Tally HSN master picker; do not type codes manually for AATO > ₹5 cr.
"Place of supply mismatch with state code"	POS in invoice does not match buyer's state from GSTIN	Either fix the POS to match ship-to state, OR (if drop-shipping) explicitly capture POS = ship-to state in voucher.
"Duplicate invoice number"	Same invoice uploaded earlier in IFF or amendment	Check IFF log for May / June. If already uploaded via IFF, remove from this GSTR-1; portal de-duplicates by invoice number within FY.
"Tax amount does not match invoice value × rate"	Rounding difference; Tally uses banker's rounding, portal uses simple rounding	Round each invoice to 2 decimals in Tally before export. F11 > Configuration > Rounding Method > Normal Rounding.

## A view of where time gets spent ## Pre-file checklist (print this for the team)

• Tally Prime updated to v5.x or later (HSN dropdown enforced)
• IRN reconciliation report downloaded for the full month
• Every B2B invoice has a matching IRN (or a documented exemption)
• Place-of-supply field manually verified on inter-state invoices > ₹50,000
• HSN codes in Tally master match the GSTN dropdown (4-digit or 6-digit per turnover)
• B2C-Large (Table 5) and B2C-Small reconciled by ₹2.5L threshold
• Tally rounding set to "Normal Rounding" (not banker's)
• JSON exported, saved to dated folder, opened in a JSON viewer to sanity-check
• Portal credentials work; MFA OTP delivery verified before upload
• EVC mobile number for authorised signatory live and reachable

## Common mistakes we see at portal upload time Symptom: "JSON upload throws 'GSTIN does not exist'." Cause: a buyer GSTIN was cancelled by their state authority but your master still shows them as active. Fix: run GSTN Search Taxpayer on your top-50 B2B buyers monthly; flag any cancelled GSTINs for immediate review and switch those invoices to B2C-Large. Symptom: "Tax computed by portal differs from JSON by ₹1-2." Cause: rounding mismatch. Tally banker's rounding rounds 0.5 toward the nearest even number; portal rounds 0.5 up. Fix: in Tally, F11 > Configuration > Rounding Method > Normal Rounding (always up at 0.5). Re-export. Difference vanishes. Symptom: "HSN code 6203 invalid for this period." Cause: you used a 4-digit HSN but your turnover crossed ₹5 cr — you now need 6 or 8 digits. Fix: bump HSN granularity in Tally master, re-export. Symptom: "Cannot file — open IFF found for the same period." Cause: you uploaded May / June invoices via the Invoice Furnishing Facility for the M2 month, and a duplicate is appearing in GSTR-1. Fix: in the portal, delete the IFF entries OR drop them from your GSTR-1 JSON — never both. Symptom: "File button greyed out." Cause: a section has "Processed with Error" but the user did not view the row. Fix: click each section, find the red error row, fix the root cause invoice in Tally, re-upload that section. ## When NOT to file today If your June IRN log has more than 5% of invoices missing IRNs, do NOT file today — file tomorrow or after. The reason: filing GSTR-1 with B2B invoices that never went through the IRP triggers a "non-e-invoice B2B" yellow flag on the portal. Your buyer's GSTR-2B will not show the credit. Better to spend July 11 generating missing IRNs (allowed up to 30 days post-invoice for AATO > ₹10 cr) and file July 12 with the ₹50 late fee than file dirty today. The other "do not file" case: if you are still under ₹5 cr AATO and your CA has been hand-keying invoices into the portal (no JSON, no Tally). The hand-key flow is slower but lower-risk — block 90 minutes after 4 pm, file by 7 pm, hope the portal is up. ## Real example — a Coimbatore textile exporter, ₹14 cr turnover The client runs Tally Prime 5.0 with a custom TDL for invoice numbering. June had 142 B2B invoices, 8 B2C-Large, 34 B2C-Small. The mismatch pattern this morning: - 4 B2B invoices in Tally but missing from the IRN log. Cause: their IRP API token expired June 18 (post-MFA renewal cycle), retry logic logged failures to a file nobody read. We regenerated the IRNs at 9:42 am. - 11 inter-state invoices had place-of-supply as Tamil Nadu (their state) instead of the ship-to state. The TDL had a default that overwrote POS at voucher save. Disabled the default, fixed manually, took 18 minutes. - 1 invoice tagged B2C-Small was ₹2,84,000 for an unregistered Bangalore buyer — should have been B2C-Large. Reclassified in Tally, re-exported. Total sprint time: 51 minutes (slightly above median because of the IRN regeneration). Filed at 11:34 am. ARN saved. We had this same conversation about hand-rolling GSTR-1 prep into our n8n + Tally automation piece — most of this is automatable, but the IRN reconciliation step still needs a human eye. The Reddit thread on [r/IndiaTax](https://www.reddit.com/r/IndiaTax/) from July 10 had a dozen CAs sharing similar morning-of mismatches. The pattern repeats: place-of-supply errors top the list, IRN gaps second, HSN drift third. ## How this connects to GSTR-3B from August The June 2025 GSTR-1 we file today auto-populates next month's GSTR-3B Table 3.1 and 3.2. For the July 2025 period (filed 20 August), Table 3 becomes [non-editable](https://taxguru.in/goods-and-service-tax/hard-locking-auto-populated-data-gstr-3b-paradigm-shift-gst-return-filing-compliance.html). This means a wrong June GSTR-1 today is fixable via GSTR-1A within the same period (before August 20), but the moment you submit GSTR-3B, the GSTR-1A window closes. The implication for your workflow: stop treating GSTR-1 as the "first draft" that you correct in GSTR-3B. Treat GSTR-1 as the final source of truth. Get the 45-minute sprint right today, and the August GSTR-3B becomes a 15-minute review. ## A code sketch for the IRN reconciliation step If you run any custom billing app alongside Tally, the IRN reconciliation can be automated. Here is the SQL pattern we use:

  -- find Tally invoices with no matching IRN
  SELECT
    t.invoice_number,
    t.invoice_date,
    t.gstin_buyer,
    t.invoice_value
  FROM tally_b2b_invoices t
  LEFT JOIN irp_irn_log i
    ON t.invoice_number = i.document_number
    AND t.gstin_buyer = i.buyer_gstin
  WHERE t.invoice_date BETWEEN '2025-06-01' AND '2025-06-30'
    AND i.irn IS NULL
    AND t.invoice_value > 0
  ORDER BY t.invoice_value DESC;
  

The IRP log is downloadable from einvoice1.gst.gov.in as a daily CSV. Most SMBs we work with import that CSV into a SQLite or Google Sheets table once a day via a scheduled cron, then run this query as part of the morning standup. For broader context on how the new GST cycle changes your filing rhythm, see our earlier GST 2.0 software-updates checklist. The hard-lock starts hitting your books from this period onward. ## FAQ ### Can I file GSTR-1 without an IRN for some B2B invoices? If your AATO is below ₹5 cr, yes — e-invoicing is not yet mandatory. Above ₹5 cr (the post-April 2025 threshold), every B2B invoice needs an IRN before it goes into GSTR-1. Missing IRNs trigger a yellow flag and buyer-side ITC issues. ### What if my Tally version is older than 5.x? Tally Prime 5.x added the HSN master dropdown enforcement. Older versions still let you type free-form HSN codes, but the GSTN portal will reject them at upload. Upgrade Tally before next month's filing; the upgrade is free for users with active TSS. ### Is the GSTR-1 due date the same for all turnover bands? Monthly filers (AATO > ₹5 cr): 11th of next month. Quarterly filers under QRMP (AATO < ₹5 cr): 13th of the month following quarter-end. Check your filing frequency in the portal under Returns > Filing Frequency. ### What is GSTR-1A and when do I use it? GSTR-1A is the amendment form for the same tax period. From July 2025 onward, since GSTR-3B Tables 3.1 and 3.2 are non-editable, GSTR-1A is the only route for same-month corrections. File GSTR-1A before submitting GSTR-3B; once GSTR-3B is filed, GSTR-1A for that period is locked. ### Can I file GSTR-1 nil if I had no sales in June? Yes. Filing is mandatory regardless of turnover. Use the "File Nil Return" button on the portal — no JSON needed, just an EVC OTP. Skipping it triggers ₹20/day for nil returns, capped at ₹500. ### What if the portal goes down at 5 pm today? Take a screenshot of the error, save it with timestamp. CBIC has historically extended due dates by 1-2 days when the portal had outages, but they will not extend without aggregate complaints. Tag CBIC's Twitter handle and your state GST commissioner. ### What is the ARN and where do I save it? ARN (Application Reference Number) is the acknowledgement after successful filing. Format: AA + 2-digit state code + month + year + 8-digit serial (example: AA0306202512345678 for June 2025 GSTR-1 from Maharashtra). Save it in your tax-filing folder; you will need it for any future GSTR-1A or audit reference. For the broader GST 2.0 roadmap from a founder's perspective, see Vivek Singh's blog. Our CRM development team has shipped the same Tally-portal bridge for clients like Radiant Finance — a finance-sector SMB where every invoice is regulated.