How GST invoicing works for your online orders
Understand the shape of GST invoicing on online orders, why the delivery state matters and where most stores quietly get their paperwork wrong.
Orders arrive from everywhere and each one needs paperwork
A physical shop supplies customers standing in front of it. An online store supplies buyers in several states in the same hour and each of those orders carries a different tax treatment on the same product. That is the whole difficulty in one sentence.
This guide describes how the mechanism works. It is not tax advice. GST law changes and its application depends on what you sell and where you are registered so a chartered accountant should confirm the treatment for your business before you rely on it.
What getting this right costs and what it does not cover
Compliance spending does not cover the tax itself and it does not cover interest or penalties arising from past errors. It also does not remove your responsibility. Whoever files on your behalf works from data you supply and incorrect data produces incorrect filings in your name.
The real costs are three. There is professional fees for filing and reconciliation which recur monthly. There is software because invoice numbering and tax computation and return-ready reports are not practical to maintain in a spreadsheet past modest volumes. And there is internal time for reconciling what the shop recorded against what your returns report. GST at 18% applies on the professional fees and the software subscription you buy as services.
Who should not build this out
If your store has not taken its first hundred orders do not build invoicing infrastructure. Issue correct invoices from whatever your platform produces and spend the money on demand instead. Businesses routinely buy an accounting integration before they have revenue and the integration then sits unused while the store closes.
Registration itself is not a free choice for everyone. The law requires registration in certain circumstances including particular cases of supply through an electronic commerce operator and there are turnover limits that differ by state and by whether you sell goods or services. Whether you fall inside those circumstances is a question for your accountant rather than something to decide from a guide.
And if you sell only through marketplaces do not build a parallel invoicing system. The operator already generates documents in a prescribed form for those orders and duplicating them creates reconciliation work with no benefit. Build your own invoicing when you begin selling direct.
How the mechanism actually works
Every taxable supply needs a tax invoice carrying prescribed particulars. Those include your GSTIN and a serial number from a continuous series and the date and the recipient details and a description with the HSN classification and the taxable value and the tax charged shown separately. The rate itself follows from the classification of the goods and rates differ widely across categories so the classification decision drives everything after it.
The split between central and state tax depends on the place of supply. Where goods move to the buyer the place of supply is generally determined by the delivery location rather than by where your warehouse sits. A supply inside your own state attracts central and state tax as two components. A supply to another state attracts integrated tax as a single component. This is why the same product at the same price produces two differently structured invoices on the same day.
Two further mechanisms matter for online sellers. Where you supply through an electronic commerce operator the operator is required to collect tax at source on the consideration it collects and that amount appears as a credit you reconcile against your own liability. And electronic invoicing through the government portal applies to businesses above a notified turnover threshold which has been lowered in stages so whether it applies to you is a question of your current turnover against the current notification.
Knowing whether your process is sound
The flattering indicator is the absence of a notice. No notice has arrived so the paperwork must be fine. Notices follow reconciliation mismatches by a long interval and silence in month three says nothing about month one.
The measure that matters is reconciliation. Each month the taxable value recorded by your shop should tie to what your returns report and the gap should be explainable line by line. Track the number of unexplained differences rather than their size because a small unexplained difference usually means a rule is being applied inconsistently and that will scale. Also track how long after month end your books are closed. A business that reconciles within a fortnight catches errors while the order details are still retrievable.
The common mistake
The most frequent error is determining tax from the billing address when the goods move somewhere else. A buyer in Delhi ordering a gift delivered to Pune produces an invoice built on the wrong place of supply and therefore the wrong tax components. One such order is a nuisance. A rule applied wrongly for a year across thousands of orders is a reconstruction exercise.
The second error costs real money. Returns and refused cash on delivery orders need the prescribed credit note treatment within the timelines the law allows. Stores that simply refund the buyer and leave the original invoice standing have reported supplies they never completed and have paid tax on revenue they never kept. On a store with heavy cash on delivery volume this is not a marginal amount.
This guide explains how something works. It is not legal, tax or financial advice, and rules change. Confirm anything regulatory with a qualified professional before you act on it.