What exactly is in the GSTR-1 JSON file?

1. The JSON is your complete GSTR-1 in the GST portal's machine format: your GSTIN, the filing period, and a block per table - b2b, b2cl, b2cs, cdnr, doc_issue (Table 13), supeco (Table 14) and hsn (Table 12).

2. Everything inside is already portal-shaped: dates as DD-MM-YYYY, one item entry per rate per invoice, HSN corrections applied, internal fields stripped. It passes the portal's own schema checks because AprilTax runs the same rules first.

3. Don't edit the file by hand - a manual edit is the #1 cause of portal rejections. Need a change? Fix it in AprilTax and download again.

4. Then upload it on the GST portal: Returns Dashboard → GSTR-1 → Prepare Offline → upload the JSON. The portal fills every table from it.