GSTR-1 JSON from marketplace exports (Myntra / Amazon / Flipkart / Meesho) — looking for CA feedback

• Table 13 Serial Numbers: Continuous internal book serial numbers should be reported in Table 13, not raw marketplace return IDs.

• JSON Portal Rejections: Portal rejections in version 3.2.4 primarily stem from special characters/over-length in hsn_user_desc, empty arrays in hsn_b2b/hsn_b2c, or negative values in Table 12 HSN summaries.

• Utility Viability: A lightweight offline JSON pre-processing utility provides high utility for bridging raw marketplace CSVs with GSTR-1 compliance without bloating accounting software like Tally.

Thank you, Sir. This matches what we saw in August.

1. Table 13 — we now put marketplace invoice serials (I2927NI…) under invoices, and a running books series for credit notes (not Myntra return IDs).

2. JSON 3.2.4 — we strip HSN user_desc/desc to the 30-character GST pattern, omit empty hsn_b2b / hsn_b2c, and keep CGST = SGST after rounding. Negative Table 12 HSN is the remaining case I want to be careful with (a state/HSN that is net returns-only).

3. Agreed it should stay a pre-step before Tally / CA filing, not a replacement.

Happy to screen-share a dummy-GSTIN JSON if that is useful. No portal login required.

Aashok — this is a genuinely useful thread, thanks for the detail. I'm actually building something in this same space — automated GSTR-1 prep from Amazon/Flipkart/Meesho exports for ecommerce sellers, plus catching things like Rule 88C period mismatches (a sale and its return landing in different filing periods) and TCS reconciliation.

The negative Table 12 HSN case you flagged — a state/HSN that nets to returns-only in a period — is exactly the kind of edge case I've been chasing down too. Would love to compare notes if you're open to it.

Not pitching anything here, just a fellow builder who'd value 15 minutes with someone who clearly handles this end-to-end for ecommerce clients. Happy to also show what I've built (dummy GSTIN, no logins needed) if useful to you. Saw your Calendly link on LinkedIn — happy to grab a slot there, or just reply here.

"Hello! I just started my career in finance and have a lot of practical tax and accounting questions that I need help with. Would you mind adding me on WhatsApp at @ CA91Rashmi  and inviting me into the discussion group? Thank you so much!"