Ecommerce Platform with GST Billing & Invoice for Online Store India 2026

Illustration of tax and finance management

If you sell products online in India, GST compliance isn't optional — it's a legal requirement once you cross certain thresholds. Yet many online sellers, especially those just starting out, find GST confusing and intimidating.

This guide breaks down everything you need to know about running a GST compliant online store in India: when you need to register, how tax calculations work, what your invoices must include, and the mistakes that get sellers into trouble.

Why GST Matters for Online Sellers

The Goods and Services Tax (GST) replaced India's complex web of indirect taxes in 2017. For e-commerce sellers, GST matters for three critical reasons:

Legal compliance. Selling online without proper GST registration and invoicing (when required) can result in penalties, interest charges, and legal action.
Input tax credit. Proper GST compliance lets you claim credit for the GST you pay on business purchases — reducing your effective tax burden.
Customer trust. B2B buyers, in particular, require GST-compliant invoices to claim their own input tax credits. Without proper invoicing, you lose business customers.

GST Registration Basics

When Is Registration Mandatory?

GST registration is required when your aggregate annual turnover exceeds:

₹40 lakh for sellers of goods (₹20 lakh for special category states like Manipur, Mizoram, Nagaland, Tripura, Meghalaya, and others)
₹20 lakh for service providers (₹10 lakh for special category states)

Important exception: If you sell through e-commerce operators (Amazon, Flipkart, etc.), GST registration is mandatory regardless of turnover. This is a provision under Section 24 of the CGST Act that many new sellers overlook.

Types of GST Registration

Regular registration — For businesses above the threshold. You charge GST, file returns, and can claim input tax credit.
Composition scheme — For businesses with turnover up to ₹1.5 crore. Lower tax rates (1–6% depending on category) but you cannot claim input tax credit or sell inter-state. Not available for e-commerce operators or sellers on e-commerce platforms.

For most online sellers, regular registration is the right choice. It gives you the flexibility to sell across India and claim input credits.

Understanding HSN Codes

HSN (Harmonized System of Nomenclature) codes are standardised numerical codes that classify goods for tax purposes. Every product you sell should be mapped to the correct HSN code, which determines the applicable GST rate.

How HSN Codes Work

HSN codes are typically 4, 6, or 8 digits long. More digits mean more specificity.
Businesses with turnover above ₹5 crore must use 6-digit HSN codes. Below ₹5 crore, 4-digit codes are sufficient.
Each HSN code maps to a specific GST rate: 0%, 5%, 12%, 18%, or 28%.

Examples

6109 — T-shirts and singlets (5% or 12% depending on price)
0902 — Tea (5%)
8517 — Mobile phones (18%)
3304 — Beauty and skincare products (18% or 28%)

Getting HSN codes wrong means charging incorrect tax — which creates problems during GST filing. Take the time to verify the correct codes for your products.

CGST, SGST, and IGST Explained

This is where many sellers get confused. GST is split into three components based on where the seller and buyer are located:

Intra-State Sales (Same State)

When you sell to a customer in your own state, the GST is split equally into:

CGST (Central GST) — Goes to the central government
SGST (State GST) — Goes to the state government

Example: If the GST rate is 18% on a product, you charge 9% CGST + 9% SGST.

Inter-State Sales (Different States)

When you sell to a customer in a different state, you charge:

IGST (Integrated GST) — The full GST amount as a single tax

Example: If the GST rate is 18%, you charge 18% IGST.

The total tax amount is the same — only the split differs. But your invoices must show the correct breakdown. Getting this wrong leads to mismatched returns and potential notices from the GST department.

GST Invoice Requirements

A GST-compliant invoice must include these mandatory fields:

Invoice number — Sequential, unique, and no longer than 16 characters
Invoice date
Seller details — Name, address, and GSTIN
Buyer details — Name, address, and GSTIN (for B2B sales)
HSN code for each item
Description, quantity, and unit of goods
Taxable value (before tax)
GST rate and amount — Shown as CGST + SGST or IGST
Total invoice value
Place of supply — The state where goods are delivered (determines CGST/SGST vs IGST)
Signature or digital signature of the supplier

Common GST Mistakes Online Sellers Make

Wrong HSN codes. Using generic or incorrect HSN codes leads to wrong tax rates and mismatched returns. Verify each product's code.
Missing place of supply. The delivery address determines whether you charge CGST/SGST or IGST. Your invoicing system must track this correctly.
Not filing returns on time. Late filing attracts a penalty of ₹50/day (₹20/day for nil returns), capped at ₹5,000 per return. Plus interest on any unpaid tax.
Ignoring reverse charge on shipping. If you use a Goods Transport Agency (GTA) for shipping, reverse charge mechanism may apply. Consult your CA for specifics.
Not issuing credit notes properly. Returns and cancellations require proper credit notes with references to the original invoice.
Mixing personal and business expenses. Only business-related purchases qualify for input tax credit. Keep clear records.

How StoreBase Handles GST

We built GST compliance directly into StoreBase because we know it's one of the biggest pain points for Indian online sellers. Here's what's included:

GST rules engine — Define GST rates by category, subcategory, or specific products. Set HSN codes once and they're applied automatically.
Automatic CGST/SGST vs IGST calculation — Based on your business state and the customer's delivery address, StoreBase automatically applies the correct tax split on every order.
Compliant invoice generation — Every invoice includes all mandatory fields: GSTIN, HSN codes, tax breakdowns, place of supply, sequential numbering, and more.
PDF invoices — Professional PDF invoices generated automatically for every order. Customers can download them from their order confirmation page.
Bulk GST rule management — Import and edit GST rules in bulk when you have a large catalogue.

Get Your GST-Compliant Store Running

GST compliance doesn't have to be complicated. With the right platform, it's handled automatically — from HSN code mapping to invoice generation to tax calculations on every order.

Get started with StoreBase and launch a fully GST compliant online store without worrying about tax calculations or invoice formatting. View our plans to find the right fit for your business.

For a complete walkthrough of launching your store, read our step-by-step guide to starting an online store in India.

Have questions about GST or store setup? Contact us — we're happy to help.

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