You sell on Amazon, Flipkart, Meesho or Myntra
Drop the GST reports they already generate. Leave them zipped. fynxIQ works out which file is which from the columns, not the filename, and reconciles the operator totals against your own.
GSTR-1 for sellers, small businesses and the people who file for them
The return has to balance before you file it.
Marketplace reports, your own spreadsheet, or a photograph of a handwritten bill book. fynxIQ builds the return, then checks it against itself. Every figure traces back to a numbered row in a named file, and nothing downloads while a number disagrees.
- Your sales data is read in your browser and never uploaded.
- Four marketplaces built in, any spreadsheet mapped once, paper bills photographed.
- Free to prepare your first returns, with every check running in full.
No card. No portal credentials. Ever.
Running right now, in this page
Cross-tally
July 2026 · sample month
| Field | Tables 4–9 | Table 12 | Difference |
|---|---|---|---|
| Taxable value | 16500.00 | 16500.00 | 0.00 |
| Integrated tax | 525.00 | 525.00 | 0.00 |
| Central tax | 45.00 | 45.00 | 0.00 |
| State tax | 45.00 | 45.00 | 0.00 |
Balanced. Ready to download.
Every figure agrees. The HSN summary is derived from the same ledger as the liability tables, so the two describe the same month and the difference column is exactly zero rather than nearly zero.
Who this is for
Three ways a month of sales arrives.
The checks are the same whichever it is, because they are checks on the return, not on the file it came from.
You write invoices by hand, in a bill book
Photograph the pages. Each one is read, and then made to prove itself — the lines against the subtotal, the tax against the rate, and the figures against the amount written in words. Nothing uncertain is entered silently.
You file for clients who send you whatever they have
A register in Excel, a marketplace export, a stack of photographs, or all three in one month. Everything lands in one ledger, and the return will not download while any part of it disagrees with any other.
The part people do not believe
A handwritten bill, proving itself.
Reading handwriting accurately is the wrong thing to promise, and we do not promise it. What a tax invoice has instead is redundancy: the same money is written four or five times over, in ways that cannot go wrong together. So the figures are not trusted because they were read well — they are trusted because they agree.
The green line is the one that does the work. Words and digits share no strokes, so a misreading of one cannot produce the same misreading of the other — a figure that matches its own words was read correctly, whatever the handwriting looked like. And the last line is the check the page cannot make about itself: only your own filing history knows which registration this buyer was invoiced under last month. Every check, and what makes it true →
Why this exists
A return can be well formed, accepted, and wrong.
We built fynxIQ after reconciling a real GSTR-1 that a popular tool had prepared and a seller had filed. It was valid JSON. The portal took it. It was also missing the entire consumer half of the HSN summary.
Table 12 as filed
580.58The HSN summary covered only supplies to registered buyers.
Tables 4 to 9 as filed
3,614.45The liability tables carried the whole month, B2B and B2C alike.
Unreconciled
3,033.87Nothing in the file said so. The gap surfaces at the annual return, or when a notice asks for a reconciliation you now have to build from twelve months of marketplace exports.
What fynxIQ does with it
BlockedTable 12 is derived from the whole ledger and asserted against every other outward table. If the difference is not exactly zero, the download stays closed and the amount is named.
The same return also counted two zero-value replacement invoices as cancellations, which understated documents issued in Table 13 by two and overstated cancellations by two. Both cases are pinned as tests. Read the full write-up.
Three steps
Download, drop, check, upload.
Download what you already have
The GST reports your marketplaces generate every month. Leave them zipped. fynxIQ works out which file is which from the columns, not the filename.
Read the checks, not just the total
Blockers name the figure that does not agree and the row it came from. Warnings explain what is unusual but legal. Notes say what was excluded and why.
Upload the JSON on the portal
Returns, GSTR-1, Prepare Offline. Compare the summary the portal generates against the figures you saw here, then submit it yourself.
What gets checked
Rules, not impressions.
Every one of these is a deterministic assertion over the finished return. They run on every plan, including the free one, because the checks are the product.
The HSN summary must cover the same supplies as the liability tables
Compared in integer paise with no tolerance. Not close to zero. Zero.
An invoice total must equal the sum of its own item lines
A document that disagrees with itself is rejected before it can be downloaded.
Tax must be the declared rate applied to the declared base
A rate of 0.03 where 3 was meant scales every figure by a hundred and still balances internally.
The fifteenth character is a checksum, and it is verified
Yours, your buyer's, and the marketplace operator's. A typo is caught here, not by the portal.
Inter-state supplies carry integrated tax and nothing else
A supply inside your own state splits across central and state tax. Getting it backwards is a blocker.
Every document reported must fall inside a declared range
And every number missing from a range is named, so you can check it against your own register.
Everything fynxIQ checks and builds → · What every one of them rests on →
Sources
Four marketplaces built in. Any spreadsheet mapped once. Paper photographed.
Amazon
Both halves of Amazon's Merchant Tax Report, read the way GST law reads them: shipments are invoices, refunds are credit notes against the original invoice, and a promotion reduces the tax as well as the base.
Meesho
Meesho splits a month across two downloads. The amounts are in one and the document numbers in the other, joined on the sub-order number.
Flipkart
Sales, returns, cancellations and replacements read from one file, with the event type deciding which is which.
Myntra
Forward and reverse movements arrive in one register, with the credit note number sitting on the return rows themselves.
Anything else
Point the fields at the columns once and any spreadsheet becomes a supported source. The mapping is saved and reused every month.
Pricing
Free to prove it. A few hundred rupees to live in it.
Every plan runs every check. What changes is how many GSTINs you file for, how many returns you prepare, and whether the AI second opinion is included.
Starter
One GSTIN, filing for yourself
Free
Prove it on your own return before you pay anything.
Start freeSeller
Up to 2 GSTINs
₹399 /month
₹332/month billed yearly
For a seller running one or two businesses across marketplaces.
See what is includedBusiness
Up to 10 GSTINs
₹999 /month
₹832/month billed yearly
Several registrations, a team, and a month-end that has to close on time.
See what is includedPractice
Up to 100 GSTINs
₹2499 /month
₹2082/month billed yearly
For accountants filing on behalf of many clients.
See what is includedQuestions
The ones people actually ask.
Common
Do I need an accountant to use fynxIQ?
No. You download the reports your marketplaces already give you, drop them in, and get a JSON file to upload on the GST portal. Where something needs a decision, fynxIQ explains what the decision is in plain language rather than asking you to know a table number.
Does fynxIQ file the return for me?
No. It prepares and checks the return and gives you the JSON. You upload it on the GST portal yourself and submit it there. Nothing is filed on your behalf and no portal credentials are ever asked for.
Which marketplaces are supported?
Amazon and Meesho are verified against real seller exports, including Amazon’s GST ready-to-file workbook. Flipkart and Myntra are supported from their published report layouts and say so until you have checked one of your own files through them. Anything else at all — another marketplace, an accounting export, a register you keep in Excel yourself — can be read on request or mapped by hand once.
My file is not from a marketplace. Can fynxIQ still read it?
Yes. Upload it and fynxIQ will tell you what every sheet in it turned out to be, one word each: orders, a finished return, a cover page, or unknown. For anything it cannot place, press the button and it works out what each column holds, then asks you about whatever it genuinely cannot settle — in whichever language you picked, as buttons rather than a form. Every arithmetic check still runs afterwards and can still refuse the return, so a wrong answer to a question costs you a corrected mapping, not a wrong filing.
Can it ask me things in Hindi, or my own language?
Yes. Pick from fourteen languages, including Hinglish written in Roman letters. Every question fynxIQ asks about your file, and the whole of the AI second opinion — what is wrong, what it costs and the steps to fix it — come back in that language. GST terms like GSTIN, HSN and taxable value stay in English because that is how they are printed on your own reports, and all numbers stay in Latin digits so you can check them against your marketplace dashboard.
I uploaded the GST ready-to-file report Amazon gives me. Is that enough?
It works, and fynxIQ converts it to the JSON the portal accepts. But it is worth knowing what it is: a finished return that somebody else prepared, in which the invoices have already been collapsed into state and rate totals. fynxIQ checks it agrees with itself, and it can check nothing beyond that, because the orders behind it are no longer in the file. Upload the transaction report for the same month as well and it reconciles the two and tells you every figure they disagree on. On a real July 2025 report, the workbook’s own HSN summary declared twenty-one rupees more tax than the rest of the same workbook.
Run it on your own month.
The free plan prepares two returns a month for one GSTIN, with every check running in full. If it finds nothing, you have lost ten minutes and gained a reconciliation.
Start free