How to file GSTR-1 step by step (with the offline JSON file)

GSTR-1 is the return in which you report all your sales of the month (or quarter) to the GST portal. Your B2B customers get their input tax credit (ITC) in GSTR-2B only from this return, so it must be filed correctly and on time.

GSTR-1 due dates

Late filing attracts a late fee and delays your B2B customers' ITC. Dates are sometimes extended — always check on the portal.

What goes into GSTR-1

• B2B — invoices to customers with a GSTIN, invoice by invoice
• B2CL — invoices above ₹1 lakh to unregistered customers in another state
• B2CS — all other small B2C sales, totalled by state and rate
• Credit / debit notes — returns
• HSN summary — totals by HSN code (B2B and B2C separately)
• Documents issued — invoice number series used
• E-commerce (Table 14) — sales through Amazon, Flipkart, Meesho etc.

Making the GSTR-1 JSON in DukanDesk

1. Enter your correct GSTIN in Settings.
2. Every item should have the right HSN code and GST rate — fix any warning.
3. Open GST Centre → choose the month (1st to the last day).
4. Tap GSTR-1 JSON — the file downloads.
5. GST portal → Returns → GSTR-1 → Prepare offline → Upload → choose the JSON file.
6. Check the summary → Submit → File with EVC / DSC.

Common mistakes

• Wrong or missing customer GSTIN — a B2B bill goes into B2C
• Missing HSN code or wrong number of digits (should be 4, 6 or 8)
• The same invoice number used twice
• A return not linked to its original invoice

DukanDesk shows most of these as warnings while making the JSON.

File it yourself or with a CA?

If you have few invoices and know the portal, filing with DukanDesk's JSON is easy. Short of time? Send your data in one tap with the GST data pack — our team files GSTR-1 and 3B and sends you the ARN. See the GST filing service.