GST Billing Software Requirements: Compliance Checklist for 2026

This guide is for business owners, accounts staff and CAs in India who are buying or commissioning GST billing software in 2026. By the end you will be able to check a demo against the mandatory invoice fields, understand the e-invoicing and e-way bill mechanisms well enough to ask the right questions, and decide which requirements are must-haves for your turnover and trade.

What a GST-compliant invoice must contain

The tax invoice is the document everything else hangs on. The CGST Rules list the particulars a tax invoice must carry, and the software should make it impossible to save an invoice without them.

Mandatory fields on a tax invoice

• Supplier's name, address and GSTIN.
• A consecutive invoice number, unique for the financial year, up to 16 characters, with letters, numbers and permitted special characters only. Series should reset each April and never repeat.
• Date of issue.
• Recipient's name, address and GSTIN if registered. For an unregistered recipient, name, address and state where the invoice value is ₹50,000 or more, or on request.
• HSN code for goods or SAC for services. The number of digits required depends on your annual turnover; check the current notification on the GST portal.
• Description, quantity and unit of measure, total value, and taxable value after discounts.
• Rate and amount of tax split into CGST and SGST (or UTGST), or IGST, plus cess where it applies.
• Place of supply with the state name, for inter-state supplies.
• Delivery address where it differs from the place of supply.
• Whether tax is payable on reverse charge.
• Signature or digital signature of the supplier, or an electronic invoice where the rules allow it.

A good gst invoice format also carries your bank details, payment terms and the buyer's PO reference, none of which are required by law but all of which reduce payment delays.

B2B vs B2C invoices

A B2B invoice goes to a registered buyer with a GSTIN, and every field above applies. The software should validate the GSTIN format, look up the buyer's legal name and state, and store the invoice for GSTR-1 reporting invoice by invoice.

A B2C invoice goes to an unregistered buyer. Recipient details are optional below the ₹50,000 value line, and for very small retail sales where the buyer does not ask for an invoice, the rules allow a consolidated invoice at the end of the day. B2C sales are reported in GSTR-1 as state-wise and rate-wise totals, with larger inter-state B2C invoices reported individually above a value limit that you should confirm on the portal. Your software should therefore tag every invoice as B2B or B2C at the moment of billing, not at month end.

Place of supply: when to charge IGST and when CGST plus SGST

GST is a destination-based tax. If the place of supply is in the same state as your registration, the invoice carries CGST and SGST (or UTGST). If it is in another state, or to an SEZ unit, it carries IGST.

For goods, the place of supply is normally where the movement of goods ends, which is the delivery address. For most services to a registered buyer, it is the buyer's registered location. The common trap is the bill-to and ship-to case: a Rajkot bearing manufacturer sells to a Mumbai trader who asks for delivery to a customer in Ahmedabad. The supply is treated as made to the Mumbai trader, so it is inter-state and carries IGST even though the goods never left Gujarat.

For the software, place of supply must be a field on every invoice, defaulted from the buyer's state but editable for ship-to cases, and the tax split must follow from that field automatically. Exports and SEZ supplies need a zero-rated option with LUT reference or IGST payment.

E-invoicing software requirements: IRN and QR code

E-invoicing adds a registration step: before a B2B, SEZ or export invoice is issued, its data is sent in a standard schema to an Invoice Registration Portal, which returns a 64-character Invoice Reference Number and a digitally signed QR code. The invoice you give the buyer must print that QR code. B2C invoices are not e-invoiced.

Who must e-invoice

E-invoicing applies to registered businesses whose aggregate annual turnover crossed a government-set threshold in any financial year since 2017-18. The threshold has been reduced several times, so check the current figure on the official e-invoice portal rather than relying on any article. Once you cross it, every B2B invoice, credit note and debit note must carry an IRN.

What the software must do

1. Build the e-invoice JSON in the notified schema from the invoice you enter, with no re-typing.
2. Send it to the IRP through a GST Suvidha Provider or direct API, receive the IRN, signed QR and acknowledgement, and store them with the invoice.
3. Print the QR code and IRN on the invoice PDF and thermal or A4 print.
4. Handle cancellation within the 24-hour window the IRP allows, and block edits to an invoice once the IRN is generated. After the window, corrections go through a credit or debit note.
5. Queue invoices when the IRP is unreachable and retry, showing a clear "IRN pending" status.
6. Validate before sending: buyer GSTIN, HSN digits, pin code and state code, unit codes, and rounding, because the IRP rejects on any of these.

E-way bill software requirements

An e-way bill is a document generated on the e-way bill portal before goods above a consignment value move by road, rail, air or ship. The general threshold is ₹50,000 per consignment, but states set their own rules for intra-state movement and some categories are exempt or always required, such as inter-state job work regardless of value. Check the current rules for your state on the portal.

The document has two parts. Part A holds the invoice details: GSTINs, place of dispatch and delivery, HSN, value and the invoice number. Part B holds the transport details: vehicle number or transporter ID.

The software should generate Part A from the invoice in one click, allow Part B to be added when the truck arrives, generate the e-way bill together with the IRN in a single call where e-invoicing applies, and support cancellation and extension. For a job work business, it also needs delivery challans for goods sent for processing and returned, with the ITC-04 reporting data captured.

Credit notes, return exports and GSTR-2B reconciliation

Billing is the front end. Returns are where GST billing software earns its keep, because your CA's time is the real cost.

Credit and debit notes

A credit note reduces the value or tax on an earlier invoice, for returns, short supply, post-sale discounts or rate errors. A debit note increases it. Both must reference the original invoice number and date, carry their own consecutive series, and be reported in GSTR-1 in the period they are issued. Where e-invoicing applies, they need an IRN too.

GSTR-1 and GSTR-3B exports

GSTR-1 reports outward supplies invoice by invoice for B2B, with B2C totals, credit and debit notes, exports, HSN summary and document series summary. GSTR-3B is the summary return where tax is actually paid, netting output tax against input tax credit.

The requirement is an export in the format the portal's offline tool or your CA's filing software accepts, with every table populated from the invoice data, no manual reworking.

GSTR-2B reconciliation

GSTR-2B is a static statement generated for you each month from what your suppliers filed, and it decides how much input tax credit you can claim. If a supplier did not file, or filed with a wrong GSTIN or amount, the credit is not available even though you hold a valid invoice.

The software should import GSTR-2B, match it line by line against your purchase register on GSTIN, invoice number, date and amount, and produce three lists: matched, mismatched and missing.

Audit trail and record keeping

GST records must be kept for a set number of years after the annual return due date, and companies registered under the Companies Act are required to use accounting software with an audit trail, meaning an edit log of every change to a transaction that cannot be disabled. Ask your CA whether that rule applies to your entity, and treat it as a requirement anyway.

GST billing software requirements checklist

Print this and score every demo. Priorities assume a registered trader or manufacturer; a retailer selling only B2C can drop the e-invoicing lines until turnover approaches the threshold.

#	Requirement	Area	Priority
1	All mandatory tax invoice fields enforced before save	Invoice	Must
2	Consecutive invoice series per financial year, no gaps or edits	Invoice	Must
3	GSTIN format validation and buyer detail lookup	Invoice	Must
4	HSN or SAC on every line with the required digits	Invoice	Must
5	B2B, B2C, bill of supply and export invoice types	Invoice	Must
6	Consolidated daily B2C invoice option	Invoice	Should
7	Place of supply field driving IGST vs CGST plus SGST	Tax	Must
8	Bill-to and ship-to handling	Tax	Should
9	Reverse charge flag and cess support	Tax	Should
10	Zero-rated exports and SEZ with LUT reference	Tax	Could
11	E-invoice JSON generation and IRP submission	E-invoice	Must above threshold
12	IRN and signed QR printed on invoice	E-invoice	Must above threshold
13	24-hour IRN cancellation and edit lock	E-invoice	Must above threshold
14	Pre-submission validation and retry queue	E-invoice	Should
15	E-way bill Part A from invoice, Part B on dispatch	E-way bill	Must for goods
16	Combined IRN and e-way bill generation	E-way bill	Should
17	Delivery challans for job work with ITC-04 data	E-way bill	Could (Must for job work)
18	Credit and debit notes linked to original invoice	Returns	Must
19	GSTR-1 export with all tables populated	Returns	Must
20	GSTR-3B summary with ITC set-off	Returns	Should
21	GSTR-2B import and three-way purchase matching	Returns	Should (Must for high purchase volume)
22	Audit trail of every edit with user and time	Control	Must
23	Role-based access and period locking after filing	Control	Should
24	Export to the accounting package your CA uses	Control	Should

What we have seen on real GST billing projects in Gujarat

JK Tech Hub has built billing, accounting and ERP systems for Gujarat businesses since 2018, and GST problems tend to come from three places. A casting unit in Metoda GIDC sends most of its output for machining on job work; its earlier billing package had no delivery challan or ITC-04 data, so the accounts team kept a parallel spreadsheet that was wrong by the time the CA saw it.

A ceramic exporter in Morbi crossed the e-invoicing threshold mid-year and discovered its billing software could only e-invoice through manual JSON upload. The replacement generates the IRN at the moment of invoicing and queues when the IRP is slow.

A distributor in Rajkot with 600 purchase invoices a month found ₹1.8 lakh of input credit sitting unclaimed because suppliers had filed late or with wrong GSTINs. Nobody had done a 2B match. The first reconciliation run produced the missing list.

The lesson across all three: the invoice format is rarely the problem. The returns, the reconciliation and the job work flow are where compliance and money are lost.

How to decide

Start from your turnover and trade. Under the e-invoicing threshold and selling B2C, a good POS with a GST invoice and GSTR-1 export is enough; see our POS billing software page for that scope. Above the threshold, or selling B2B with goods movement, you need items 11 to 17 as well, and the accounting and GST billing software page describes that build. A manufacturer with job work or many purchase invoices should insist on items 17 and 21 from day one. Score three demos against the table, and choose the one that shows the most Must items live, on your own item and party data.

Related reading and next step

• Accounting and GST billing software with e-invoicing and e-way bill
• POS billing software for retail and B2C billing
• Manufacturing ERP with job work and ITC-04 support
• How to write a requirements document before asking for quotes
• ERP software in Rajkot for traders and manufacturers

Send your turnover band, trade and the checklist rows you have marked Must through the contact page or on WhatsApp at +91 7265004040, and you will get a fixed quote for a GST billing system that covers them, usually within three working days.