The photocopy pile, written down.

GSTIN checksums, HSN format, totals that close, Tally import, and when you should keep Clear or Busy instead. No labour fairy tales. No invented percentages.

Start here · GSTIN

A swapped digit still looks like a GSTIN. Recheck the checksum.

Format can pass. Mod-36 is the cheap catch before ITC. Worked example on 27AAPFU1234A1ZF, from the validator we actually ship.

Read the GSTIN post

GST & ITC

Follow ₹10 lakh as it splits three ways

Net to supplier, TDS to income tax, ITC on its own track. One payment, two taxes, zero mixing.

4 Sep 2026

No GST on the freight bill. Look in the mirror.

RCM turns the tax around onto you. The annotated bill, the Tally entries, the file.

4 Sep 2026

The storekeeper counted 96. The bill says 100.

Two-way checks price, three-way checks quantity. The factory habit that ends short-supply disputes.

4 Sep 2026

Your supplier sent a debit note. It is not a bill.

Looks like a purchase, acts like the opposite of a credit note. The drawer it belongs in.

4 Sep 2026

The invoice was perfect. The truck was still detained.

Movement paper vs money paper. What AP checks on each before filing.

4 Sep 2026

The mail said e-invoice. The attachment was just a PDF.

The print is not the invoice. The two-minute IRN check before you post.

4 Sep 2026

Your goods left the gate. No sale happened.

Challans out, goods back, ITC kept. Three papers, one loop, one register.

4 Sep 2026

Pending in IMS: your supplier's button

Accepted, rejected, or ignored. What each does to 2B and the weekly chase that keeps it whole.

4 Sep 2026

ITC has an expiry date: the 16(4) clock

Earlier of 30 November and the annual return. The October playbook that keeps the year's credit.

4 Sep 2026

HSN on the invoice, not a rate table from a blog

4, 6, 8 digits. Confirm rates on CBIC. Common factory headings without pretending they are a tariff.

4 Feb 2026

HSN validation: format first, directory second

2/4/6/8 digits block. Directory is a snapshot: shadow warns, live is opt-in. Empty HSN does not block today.

27 May 2026

Checks before you claim ITC

What the orchestrator actually blocks vs directory shadow vs the duplicate key. Interest: read section 50, not a blog rate.

18 Mar 2026

CGST/SGST vs IGST from the GSTIN state code

First two characters. Same state vs not. Arithmetic can still close on a wrong regime.

4 Mar 2026

When the printed total never summed

Lines, taxable, tax, total. Default tolerance ±₹1 because that is the validator. Round-off is not a ₹50 gift.

18 Feb 2026

Same invoice twice, one GSTIN a digit off

Uniqueness is invoice number plus seller GSTIN when both exist. Empty GSTIN rows are not forced unique.

8 Apr 2026

GSTR-2B vs books: not always a clerk error

Supplier not filed, timing, and dirty vouchers. Clean entry only fixes the gaps you caused.

22 Apr 2026

No IRN on the photocopy? The math still has to close

IRN is GSTN proof. A bad scan is not. Confidence is not a calibrated rupee risk.

13 May 2026

Place of supply is not the GSTIN state code

Printed POS if we extracted it. Else buyer prefix. No geocoder. Regime still has to match.

3 Sep 2026

Composition invoices: post the bill, do not claim ITC

No composition classifier. Blank tax should not become 18%. Confirm scheme on the portal.

4 Sep 2026

Credit notes in the pile are not purchase vouchers

Page classing has no credit-note label. Bake-off them. Wrong Tally type lies in the books.

5 Sep 2026

Section 16: the gate is not the statute

Checksum and math prove the document. Tax paid and 16(4) still need the Act and 2B.

8 Sep 2026

GSTR-1 vs 2B vs 3B vs the books

Four piles. We file none of the GSTN ones. Dirty Tally is the pile we can clean.

9 Sep 2026

Cancelled GSTIN still checksums

Status is taxpayer search. We do not call GSTN live. Do not invent a live number to export.

10 Sep 2026

Invoice date vs scan date vs Tally

invoice_date is required. We do not pick FY. Day-first paper. Map the column.

11 Sep 2026

Same stamp, different PAN in the GSTIN

Characters 3-12. Checksum can pass. We do not block Tally-master mismatch today.

12 Sep 2026

UTGST is not SGST you can ignore

Intra bucket with CGST. Codes in gstin.py are a helper. Portal wins.

15 Sep 2026

Goods and freight on one invoice

Format is digit shape. We do not rewrite chapter 72 onto a freight line.

16 Sep 2026

Round-off rows: keep in sum, do not GST

plus/minus 1 rupee is a product default, not a law. Do not tax 0.40 of steel.

17 Sep 2026

Challan in the bundle: not an invoice

pageclass.py votes invoice/challan/lorry/other. Credit notes not yet. Bake-off it.

18 Sep 2026

RCM: blank tax columns are not zero

We do not auto-classify RCM. Missing tax goes to review. Portal and CA decide.

19 Sep 2026

XML, CSV, or Excel: use what you have

We ship all three. Masters first. Do not migrate your format for a capture tool.

22 Sep 2026

Map 200 vendor names once

Scan-name to Tally-ledger. Build once. Reuse every batch. We do not invent names.

23 Sep 2026

Docsumo reads many documents. We prove GST photocopies.

Horizontal IDP vs GST gate. Compare on your worst scans, not a clean demo.

24 Sep 2026

Zoho Books vs Tally: ledger choice, not capture

Both are ledgers. We feed Tally. Do not migrate books to fix photocopies.

25 Sep 2026

Build your own OCR vs buy the gate

OCR is the demo. Validators, review, Tally mapping are the product. Six months to build.

26 Sep 2026

The CA's 2B sheet is late

Clean vouchers shrink self-inflicted gaps. We do not replace the sheet.

27 Sep 2026

NEEDS_REVIEW: the queue is the product

Two outcomes, not three. No "pretty sure" that still writes Tally.

28 Sep 2026

The meter counts pages, not invoices

1.40 to 40K, 1.20 after. Three pages is three pages. Published on /pricing.

29 Sep 2026

How straight-through is measured

Measured on your paper. Not a lab PDF. Numerator and denominator explained.

30 Sep 2026

India-hosted. Single tenant.

No shared training. On-prem not default. Read /privacy.

1 Oct 2026

The CA wants to see the crop

Audit trail: scan, validator log, who confirmed. Not a confidence badge.

2 Oct 2026

Build for the clerk, not the CFO

Keyboard first. Evidence beside the field. No mouse tour.

3 Oct 2026

When not to buy EntryLedger

No photocopy tail, not on Tally, need 2B, need on-prem, want one suite. This page should lose deals.

4 Oct 2026

Ingest is not the gate

Upload live. Email and folder designed. Same gate after ingest.

5 Oct 2026

Lorry receipts: not a tax invoice

pageclass votes lorry. But GSTIN + amounts may still pass the gate. Score it.

6 Oct 2026

Why the tolerance is 1 rupee, not 0

Paisa round-off is normal. 50 is not. Default, not CBIC.

7 Oct 2026

Factory AP stack: four jobs

Books, filing, capture, people. We are the third. Buy one layer at a time.

8 Oct 2026

Buyer GSTIN required for auto-export

No buyer GSTIN, no export. Fill from master in review. Not a guess.

9 Oct 2026
Try the gate on five of your scans

Not a clean PDF demo. Photocopies. Watch checksum and arithmetic, not a confidence badge.