What must a GST billing app be able to do?

At minimum it must make a valid tax invoice with your GSTIN, HSN or SAC codes, and the correct CGST and SGST or IGST split based on the place of supply. Beyond that, look for an item master, a khata for payments, GST reports for filing, and support for e-invoice and e-way bill if your turnover or transactions require them.

When do I need e-invoicing?

E-invoicing applies to registered businesses above the turnover threshold notified by the government, which has come down in stages. If you cross the current threshold you must generate invoices through the government portal and carry an Invoice Reference Number and QR code. A billing app that supports e-invoice can push the invoice and pull back the IRN so you stay compliant.

When is an e-way bill required?

An e-way bill is generally required for the movement of goods above a set value, commonly fifty thousand rupees, whether the sale is within a state or across states, subject to state rules. A billing app that generates the e-way bill from the same invoice saves you re-entering the details on the portal and keeps the document with the bill.

Should my GST billing app work offline?

It helps if it can. A shop in an area with patchy signal needs to bill even when the connection drops, then sync when it returns. Cloud apps that also cache locally give you the best of both, always-current data across devices plus the ability to keep billing during an outage. Ask how the app behaves with no signal before you rely on it.

Is a mobile GST billing app enough, or do I need desktop?

For most small and mid-size businesses a mobile app is enough and often better, because you bill wherever the customer is and the data syncs to one account. A desktop makes sense for high-volume counters with a keyboard and barcode scanner. The strongest tools give you both, so counter staff use desktop while owners and field staff use the phone.

GST Billing App: What to Look For (2026)

Choosing a GST billing app is not about which one has the longest feature list. It is about which one gets the tax right, keeps you compliant as the rules tighten, and fits the way you actually sell. A wrong CGST figure or a missing HSN code turns into a mismatched return and a notice later. This guide sets out the features a GST billing app must have, then covers the two decisions people get stuck on, online versus offline and desktop versus mobile.

The tax split done correctly

The single most important job of a GST billing app is to apply the right tax. For a sale within your own state, the tax splits into CGST and SGST at half the rate each. For a sale to another state, the whole amount is IGST. The app decides this from the place of supply, which is usually the buyer location, so it must ask for or infer that correctly. If a tool cannot tell a local sale from an interstate one and split the tax accordingly, it is not a GST billing app, it is a calculator with a logo.

HSN and SAC codes

Every good or service on a GST invoice carries an HSN code for goods or a SAC code for services. The number of digits you must show depends on your turnover, and larger businesses show more digits. A proper GST billing app lets you store the HSN against each item once, so it prints on every invoice without you looking it up. This matters because a wrong or missing HSN is a common reason returns get flagged.

Getting the code right the first time saves rework at return time, because the GST portal groups your sales by rate and HSN. If your invoices carry inconsistent or missing codes, the summary you file will not tie out and you spend hours reconciling. Storing the correct code once against each product, and letting the app carry it forward, keeps every future bill consistent and your filing clean.

E-invoice and e-way bill

As your business grows, two compliance features move from optional to essential. E-invoicing applies once your turnover crosses the notified threshold, and it means generating each invoice through the government portal so it carries an Invoice Reference Number and a QR code. An e-way bill is required for moving goods above a set value, commonly fifty thousand rupees. A capable GST billing app connects to both, so you push an invoice for its IRN or generate the e-way bill from the same screen rather than re-keying everything on the portal.

E-invoice: the app sends the invoice to the portal and stores the IRN and QR code on the bill.
E-way bill: the app builds the e-way bill from the invoice details and keeps the number with the record.
Both together: you avoid double entry and keep the compliance documents attached to the sale.

Even if you are below these thresholds today, choosing an app that already supports them means you will not have to switch tools when you cross the line.

Reports that make filing easy

A GST billing app should hand you the numbers your return needs. At filing time you want a summary of your outward sales, the tax collected split by rate, and a list broken down the way the GST portal expects. Without these you are back to adding up bills by hand. Look for a sales report, a tax summary and an outstanding report, at a minimum. The first two save you at filing, and the third keeps your cash coming in.

Get the free IndiaCRM billing app

IndiaCRM does GST invoicing, khata and inventory in one free app for iPhone and Android, no per-user fees. Download the app or see GST billing.

The must-have checklist

Online versus offline

A lot of Indian billing happens where the signal is not reliable, a basement shop, a rural mandi, a moving delivery van. A purely online app stops working the moment the connection drops, which is a real problem at a busy counter. A purely offline app avoids that but leaves your data trapped on one device, with no sync and no backup.

The sensible middle is a cloud app that also works offline and syncs when the signal returns. You keep billing during an outage, and once you are back online every device shows the same current data. Before you commit, test the app with your phone in airplane mode, make a bill, then reconnect and confirm it synced. If the answer is not clear, ask the vendor directly how the app behaves with no signal.

Desktop versus mobile

The old assumption was that serious billing needs a desktop. For a high-volume retail counter with a keyboard and a barcode scanner, a desktop still helps. But for most small and mid-size businesses in India, a mobile app is not a compromise, it is the better fit. You bill at the counter, on delivery and at the client site from the same device, and the data lands in one account the owner can see from home.

The strongest setup supports both, so counter staff bill on a screen while owners and field staff use the phone, all against one synced account. That is the model behind the free IndiaCRM app, which keeps GST billing, khata and inventory together with no per-user fee. For the fields behind a compliant bill, see the invoice format guide, and for making bills on the go, the invoice maker guide and the bill book guide.

How to decide

Start with compliance, since getting the tax wrong is the costliest mistake. Confirm the app splits CGST, SGST and IGST correctly, stores HSN per item, and supports e-invoice and e-way bill if you are near those thresholds. Then check that it gives you the three filing reports and a khata. Finally, match the platform to how you sell, favouring an app that runs offline and on both phone and desktop. Work through those in order and you will land on a tool that keeps you compliant today and does not need replacing when you grow. To go deeper on how billing fits the rest of your operations, read what CRM software is, then open GST billing software or download the free mobile app.