How it works

Six stages, none of them hidden.

The pipeline is deliberately linear. Each stage takes the previous stage’s output and adds nothing you cannot see, which is what makes every figure in the finished return traceable back to a numbered row in a named file.

Try it on your month Which reports to download

Stage five, live

Cross-tally

July 2026 · sample month

Field	Tables 4–9	Table 12
Taxable value	16500.00	16500.00
Integrated tax	525.00	525.00
Central tax	45.00	45.00
State tax	45.00	45.00

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.

Stage 01

Archives are opened and tables are found

Zips are expanded, spreadsheets are read as spreadsheets rather than dissolved into their parts, and each sheet is examined for the columns that identify a source. Filenames are ignored: "report (1).zip" is a normal thing to have on disk.

Stage 02

Every row becomes one canonical ledger line

Amazon's ninety-column row and Meesho's twenty-column row arrive in the same shape: document type, number, date, place of supply, HSN, rate, base and tax, in integer paise, with a pointer back to the file and row it came from. After this point nothing knows which marketplace anything came from.

Stage 03

Duplicates collapse and large B2C invoices are promoted

Each line carries a natural key, so the same report uploaded twice cannot double turnover. Inter-state consumer invoices above one lakh move to Table 5, a decision that can only be made at document level rather than per line.

Stage 04

Tables are built from the same ledger

Every section reads the one ledger, including the HSN summary. That is the whole reason Table 12 cannot come out short: there is no separate path for it to be built from.

Stage 05

The return is checked against itself

Cross-tallies, document totals, tax arithmetic, check digits, tax heads, rate legality, duplicate document numbers, series coverage. Blockers stop the download. Warnings explain what is unusual but legal. Notes say what was excluded and why.

Stage 06

You upload it, and you submit it

fynxIQ hands you the JSON. On the portal: Returns, GSTR-1, Prepare Offline, upload. Compare the summary the portal generates against the figures you saw, then submit. Nothing is filed on your behalf and no portal credentials are ever requested.

What to download

The reports each marketplace gives you.

Amazon

MTR B2C report, MTR B2B report, GST ready-to-file workbook

Open Seller Central, then Reports, then Tax Document Library.
Download the Merchant Tax Report for the month. Take both the B2C and the B2B file.
Leave them zipped and drop both in. Which is which is worked out from the columns.

What goes wrong with Amazon files →

Meesho

TCS sales, TCS sales return, Tax invoice details

In Supplier Panel, open Payments, then GST, and download the TCS zip for the month.
From the same screen download the Tax Invoice zip for the same month.
Drop both zips in. Without the second one, Table 13 cannot be built and fynxIQ says so.

What goes wrong with Meesho files →

Flipkart

GST sales report, GSTR return report

Open Seller Dashboard, then Reports, then GST Reports.
Generate the Sales Report for the month and download it.
Add your Flipkart TCS registration once under Settings. Every state is derived from it after that.

What goes wrong with Flipkart files →

Myntra

GST sales register

Open Partner Portal, then Finance, then GST reports.
Download the sales register for the month.
Add your Myntra TCS registration once under Settings.

What goes wrong with Myntra files →

After the download

On the portal itself.

Sign in at the GST portal, then Returns Dashboard, choose the financial year and the return period, and open GSTR-1. Choose Prepare Offline, then Upload, and select the JSON fynxIQ produced.

The portal takes a few minutes to process it and then shows a summary. Compare that summary against the figures you saw in fynxIQ before you do anything else. They should match exactly; if they do not, something was uploaded that was not what you prepared.

Then generate the summary, review Tables 4 to 14 on screen, and submit. Filing is yours to do, on your own credentials, which is the only arrangement under which a tool can honestly say it never files something you have not seen.