Fortax Gstr2b Reconciliation

GSTR-2B reconciliation

Needs Python 3 and internet: runs scripts/fortax.py (the Fortax engine on ai.fortax.in; your file is processed and not stored).

Two kinds of match, never mixed

• Match (the engine). Same supplier GSTIN, document type and invoice number (zero padding and separators ignored), taxable value and tax within the tolerance (₹1 by default). Buckets: matched, mismatch, missing in 2B, missing in books, and "probable" (number written differently, same amounts). Every amount, total, count and 3B figure in its reply is the engine's. Never add up, recompute or re-list them.
• Judgement (you). Only what the rules could not pair, and only from the pairs the engine hands you.

Step 1 — the files

• Purchase register for the month, .xlsx or .csv, from any accounting software (Tally, Busy, Zoho, an ERP, Excel): supplier GSTIN, supplier's invoice number (the supplier's number, not your voucher number), invoice date, document type (invoice / credit note / debit note), taxable value, IGST, CGST, SGST, cess. Rows with no supplier invoice number cannot match — list them for the CA to fix at source.
• GSTR-2B for the same month and GSTIN. Look in the folder where the CA drops files and in <Client>/<FY>/GST/<YYYY-MM>/ first. A file with "2B" in its name and this GSTIN or period is already there -> use it, skip the portal.

Step 2 — getting 2B from the portal (only if no file)

GSTR-2B for a month is generated on the 14th of the next month. Asked for August before 14 September -> say it is not out yet; offer GSTR-2A only if the CA wants a provisional look.

The CA logs in, in their own browser. Username, password, captcha and OTP are theirs; never type or store them. Download only — nothing on this path submits, files or pays.

After the CA says they are logged in, either drive the page with your browser tool (Claude in Chrome, a Playwright/browser MCP, or the Codex browser) — read the page before every click, element references change on each page — or, if you have none, give the CA this click path:

1. Check the GSTIN. The dashboard must show this client's GSTIN. A saved session can belong to another client; if it does, ask the CA to log out and log in to the right one.
2. Returns Dashboard. Services -> Returns -> Returns Dashboard (or the "Return Dashboard" button on the home page).
3. Period. Financial Year (April–March holding the month), Quarter, Period = the month -> Search.
4. GSTR-2B tile. "Auto-drafted ITC Statement GSTR-2B" -> Download (not View).
5. JSON. Choose Download JSON file / Generate JSON file to download. If it says the file is being generated, wait a few seconds and click again. A large client's 2B can come in several parts — download every part.
6. File it. Move the download(s) from the Downloads folder into <Client>/<FY>/GST/<YYYY-MM>/, named with GSTIN and period. If only Excel is offered, download it — the engine reads the portal's 2B workbook too (amendment sheets are listed, not merged).

The portal changes its menus. If a step is not on the page, find the same thing by its words ("GSTR-2B", "Download", "JSON") and finish; tell the CA what the path was now.

Never click Submit, File, Proceed, Save as draft, Generate summary or anything that changes a return. Never download for a GSTIN other than the client's.

Step 3 — run the engine

python3 scripts/fortax.py gstr2b --g2b "<2B.json|zip|xlsx>" --books "<purchase_register.xlsx>" \
  --gstin 27ABCDE1234F1Z5 --fp 082026 --company "Sharma Traders" [--tolerance 1] [--out <folder>]

Writes next to the register: GSTR2B_recon_<GSTIN>_<MMYYYY>.xlsx, _summary.txt, and _pairs_to_judge.json when there are leftovers for you. A 2B of another GSTIN is refused; a 2B of another month is flagged — get the right one. Several 2B parts: run per part or ask the CA for the single zip.

Step 4 — judge the pairs

When the reply ends with a NEXT STEP and pairs, read _pairs_to_judge.json. For each: supplier, both numbers, both dates, both amounts.

• Same document: a typo or transposed digits (771 / 717), a dropped prefix or FY suffix (45 / TS/45/26-27), a separator the rules missed, rounding of a few rupees, dates within a few days.
• Not the same: two different invoices of one supplier with similar amounts; dates weeks apart; numbers sharing digits by chance. Never pair on amount alone. When unsure, leave it out.

Write the ones you accept to a file, e.g. ai_matches_082026.json:

[{"gstin": "27AAACX1234A1Z9", "books": "45", "g2b": "TS/45/26-27", "reason": "same invoice, FY suffix dropped in books"}]

Every item needs all four fields — copy gstin, books and g2b exactly as listed in the pair. Rerun the same command with --ai-matches ai_matches_082026.json. The engine applies them only between leftovers of that supplier, marks them as AI-matched, and refuses any that do not fit — say which were refused.

Step 5 — read the result out

As the summary says it, then in plain words:

• ITC as per books and as per 2B; claim now; what can be claimed after the CA confirms the probable, AI-matched and mismatch rows; at risk (in books, not in 2B).
• Your matches, each with its reason, and that the CA confirms them.
• Missing in 2B by supplier; missing in books; ITC not available as per 2B; reverse charge.
• Register rows with no supplier invoice number.
• The GSTR-3B Table 4 figures, labelled "as per 2B, check before use" — they feed fortax-gstr1-and-3b.
• The workbook path.

Step 6 — supplier follow-up (drafts only)

If documents are missing in 2B, offer one draft per supplier listing its invoices, dates and tax, asking them to file or amend GSTR-1 / IFF. Write the drafts to a file and show them; the CA sends them from their own mail. Do not suggest WhatsApp unless the CA asks.

What you say about ITC

• ITC is claimed only on documents in 2B with ITC available (section 16(2)(aa) CGST Act). Missing in 2B is not claimed "to be safe" — it waits for the supplier.
• Mismatch: take the lower of books and 2B until the difference is explained.
• Reverse charge: pay the tax in cash first, then claim the credit in the same month.
• Credit notes in 2B cut ITC even if not booked — say so when "missing in books" has credit notes.
• Section 17(5) blocked credit and Rule 42/43/37 reversals are removed in the 3B working, not here.

Never

• Recompute a total, a bucket count or a 3B figure.
• Match anything yourself outside --ai-matches, or call a match certain.
• Change the client's purchase register or send a supplier mail — draft, and the CA decides.
• Type the CA's portal password, captcha or OTP.