About
Preparing GSTR-1 with the offline utility often ends the same way: the JSON file will not generate, or the portal refuses it, and nothing says why. People close and reopen the tool, wait, and try again.
was built to remove that guesswork. It reads the same CSV files, checks every row, and tells you in plain words which row and which column to fix. It writes the JSON file only when the data is clean, and it checks the file's own shape against the fields the portal allows, because one extra field is enough to make an upload fail.
It is made by , .
What it checks
Every check runs before a JSON file is written, so a bad file never reaches the portal.
- GSTIN
- Format and check digit, so a mistyped digit is caught here instead of on the portal.
- Numbers and dates
- Invoice and note numbers up to 16 characters with allowed characters only. Dates that exist and fall inside the return period.
- Place of supply and rate
- A valid state code and a GST rate the portal accepts.
- Invoices with several rates
- All rows of one invoice must agree on date, value and place of supply. Rows are grouped into a single invoice.
- HSN summary
- 4, 6 or 8 digits, valid unit codes, and rows with the same HSN, unit and rate combined into one line.
- File format
- No field the portal's format does not allow. A single extra field is enough for the portal to say "File could not be uploaded", often with no further detail.
- Totals
- A summary of taxable value and tax by section, to compare with your books, and a warning when HSN totals do not match the invoices.
From CSV to upload in three steps
- Add the CSV files you already export for the offline utility: B2B, credit notes, HSN and so on. The tool recognises each file by its column names.
- Read the check report. Each problem names the file, the row, the column and what is wrong. Fix it in your sheet and add the file again.
- When the report is clear, download the JSON file and upload it on the GST portal. Large data is split into parts below the portal's size limits.
What it does
- Reads CSV files for B2B, credit and debit notes, B2CS, HSN, nil-rated and documents issued.
- Creates the JSON file and splits it into parts when it is too large for one upload.
- Shows totals by section so you can compare them with your books.
What it does not do
- It does not log in to the GST portal, upload anything or file a return. You do that.
- It cannot know whether a GSTIN is registered and active, or whether an HSN code exists in the portal's master list. It checks format and check digits only.
- It is not tax advice. Read the disclaimer.
What has been tested on the portal
Last checked , version .
| Section | Status |
|---|
GST rules and the portal's file format change often. When a section is marked beta, test it with a small upload before you rely on it, and tell us what the portal says so we can fix it.
Questions
Does my invoice data leave my computer?
No. The checks run in your browser. We store your email address, your subscription status and the list of GSTINs you add, nothing from your CSV files. Your saved files and client names are kept only in your own browser and are deleted when your billing period ends.
Does it file my return?
No. It prepares the JSON file. You upload it on the GST portal and file the return yourself.
Which accounting software does it work with?
Any software that can export CSV files with the same column names as the offline utility's templates. The column names for each file are listed inside the tool.
Do I need internet?
You need internet to log in and open the tool. The checks themselves run on your device.
The portal still rejected my file. What now?
Email us the portal's error message and the JSON file with names and GSTINs removed. We will find the cause and fix the tool. Our refund terms apply.
Can I use my account on two computers?
One account is open on one computer at a time. If you log in on a second computer, the newest login wins and the earlier session is locked out.
Can I change my GSTIN list?
Yes. The list can be changed every 30 days on every plan. Extra packs last for the current 30-day period.
Contact
Write to with questions, error messages from the portal, or a CSV layout we should support.