GSTR-1 and GSTR-3B: What E-commerce Sellers Must Know

GSTR-1 (outward supplies) and GSTR-3B (summary return with tax payment) are the two filings every GST-registered marketplace seller deals with monthly, and both depend on sales data that ultimately needs to tie back to your settlement reports.

GSTR-1 reports your outward supplies — essentially, what you sold and the tax on it. For marketplace sellers, this should reflect actual sales, not settled amounts; a sale is a sale for GST purposes regardless of whether the marketplace has paid you yet. This is a common point of confusion: don’t report only what’s settled and skip pending orders.

GSTR-3B is the summary return where you declare total tax liability and claim input tax credit, including the TCS your marketplace has collected on your behalf (visible in your GSTR-2B). If the TCS you’re claiming doesn’t match what the marketplace actually reported, the mismatch surfaces here — which is why TCS reconciliation against settlement data matters even for sellers who otherwise never touch their raw settlement reports.

Returns and cancellations need to flow through as credit notes in your GSTR-1, adjusting your originally reported liability — skipping this step means you’re paying GST on sales that were later reversed.

The sequencing that avoids most filing-time scrambles: reconcile settlements against sales monthly (catching missing payments and wrong deductions early), and separately verify TCS figures against GSTR-2B before filing GSTR-3B — rather than discovering a TCS mismatch during the filing itself, when there’s much less room to investigate before the deadline.