GST for E-Commerce Sellers in India: Filing Deadlines, TCS, and Common Mistakes

GST is one of the most misunderstood obligations for Indian e-commerce sellers. Some sellers believe they can wait until they are profitable before registering. Others do not realise that marketplace sellers face different rules from regular businesses. Getting this wrong costs real money — late fees, interest at 18% per annum, and the risk of GST notices that tie up your seller account.

This guide covers the key rules as they apply specifically to marketplace sellers, not just businesses in general.

Who Must Register for GST

For most businesses, GST registration becomes mandatory when annual turnover crosses ₹40 lakh (₹20 lakh for services, ₹10 lakh in special category states). But for e-commerce sellers — anyone selling through a marketplace like Amazon, Flipkart, or Meesho — there is no threshold. GST registration is mandatory from the very first rupee of sales, regardless of your annual revenue.

This is a hard rule that catches many new sellers by surprise. Even if you sell only ₹5,000 worth of products in your first month, you need a GSTIN to list on these platforms. Shopify is different — if you are running your own store, the standard threshold applies. But the moment you also list on a marketplace, you need registration.

How GST TCS Works for Marketplace Sellers

Every marketplace is legally required to deduct TCS (Tax Collected at Source) at 1% on the net value of taxable supplies made through their platform. This means before Amazon or Flipkart settles your payment, they deduct 1% and deposit it with the government against your GSTIN.

You can see this deduction reflected in your GSTR-2B each month — it appears as a credit that you can use to offset your GST liability. If your outward GST liability is ₹50,000 and your TCS credit is ₹8,000, you only need to pay ₹42,000 in cash. The credit does not automatically apply — you must claim it during your return filing.

Filing Deadlines You Cannot Miss

• GSTR-1 (11th of every month): Report all outward supplies (sales) for the previous month. Every B2C invoice you generated, every credit note for returns, every amendment to prior invoices. Late filing attracts ₹50/day (₹20/day for nil returns).

• GSTR-3B (20th of every month): Summary return where you report total outward and inward supplies, claim ITC, and pay any net GST liability. This is where your actual payment happens. Missing this incurs interest at 18% per annum on unpaid liability plus a ₹50/day late fee.

• GSTR-9 (31st December for the previous financial year): Annual return consolidating all your monthly filings. Required if your aggregate turnover exceeds ₹2 crore. For smaller sellers, filing is optional but recommended to close out the year cleanly.

• GSTR-2B (auto-generated by 14th of every month): Not something you file — it is generated by the system and shows all the ITC available to you based on your suppliers' and the marketplace's filings. Check this every month before paying your liability.

The Most Common GST Mistakes Marketplace Sellers Make

• Not claiming TCS credit: Marketplaces deposit TCS against your GSTIN every month. It appears in GSTR-2B. Many sellers pay full GST without claiming this credit — effectively paying 1% more than they owe every single month.

• Reporting GMV instead of net revenue: Your GST liability is on the selling price (excluding GST). It is not on the amount the buyer paid including GST. Reporting the wrong base inflates your tax liability.

• Missing credit notes for returns: Every return is a reversal of a taxable supply. You must issue a credit note and report it in GSTR-1 to reverse the GST already reported on the original sale. Missing this means you pay GST on revenue you never actually received.

• Ignoring Input Tax Credit on purchases: Every GST-registered vendor you buy from — packaging, raw materials, software subscriptions — generates ITC that reduces your liability. Sellers who buy without collecting GST invoices lose this credit permanently.

• Using wrong HSN codes: Each product type has a specific HSN (Harmonised System of Nomenclature) code that determines its GST rate. Using the wrong HSN code on your invoices and returns creates mismatches that attract notices.

Composition Scheme: What Marketplace Sellers Cannot Use

The Composition Scheme allows eligible small businesses to pay a fixed flat-rate GST (1–5% depending on category) instead of the standard rates, with minimal filing requirements. It sounds appealing for small sellers. But marketplace sellers are explicitly excluded from the Composition Scheme.

If you sell through Amazon, Flipkart, or any other marketplace, you must file under the regular scheme regardless of your turnover. This is non-negotiable — and attempting to use Composition Scheme as a marketplace seller exposes you to back-tax demands plus interest.

Practical Steps to Stay Compliant

Download your settlement reports from each marketplace monthly and reconcile the sales figures against what you report in GSTR-1. The numbers should match. Any gap is either an unreported credit note or a data entry error — both of which can attract scrutiny.

Use accounting software that auto-imports your marketplace settlement data and maps it to GST return fields. The manual approach — pulling settlement CSVs and entering figures by hand — is error-prone at scale and takes hours each month that could be avoided.