Everything a business actually needs to know about gst service invoice, in the order it matters — applicability first, then the flow, then the fields that cause rejections.
What changes on your invoice
The commercial content does not change. What is added is the IRN and the signed QR code, both of which have to be printed on the invoice given to the customer.
What does change is tolerance for incomplete data. An invoice missing an HSN, carrying a malformed GSTIN, or with a place of supply that contradicts the parties will simply be rejected. Software that let those through quietly before will now fail loudly.
That is, on balance, an improvement — the errors were always there, they were just discovered by the customer instead of by the portal.
What e-invoicing actually is
The name is misleading and it causes most of the confusion here. E-invoicing does not mean emailing an invoice, or producing it on a computer. Businesses have done both for decades without it being e-invoicing.
It means reporting the invoice to an Invoice Registration Portal before it is issued, and receiving back an Invoice Reference Number and a signed QR code. The invoice is not valid without them. So the invoice is registered with the government first and given to the customer second — which is a change to the order of operations rather than to the document.
It applies above a turnover threshold that has been lowered several times since introduction, and some categories are excluded regardless of turnover. Whether it applies to you is therefore a question with a current answer rather than a settled one: check the notification in force for your own turnover.
What it is not: it is not a return, it does not replace GSTR-1 — though reported invoices feed into it — and it is not the same thing as an e-way bill, which is about moving goods.
What matters in your billing software
- Complete party masters — GSTIN and state on every registered customer, validated in format.
- HSN or SAC on every line, without exception.
- Place of supply derived, not chosen, so it can never contradict the parties.
- A clean, consecutive invoice series — duplicates are a rejection cause.
- Correct document types for credit and debit notes, referencing the original.
- Discipline about editing. A registered invoice cannot be altered; corrections are cancellation within the window or a credit note.
- Billixo enforces the first four by design, which is most of what the portal is checking.
The flow, step by step
- Confirm whether e-invoicing applies to you, based on the current turnover threshold.
- Complete your masters: GSTIN and state on parties, HSN or SAC on every item.
- Raise the invoice in your billing system as normal.
- The structured invoice is sent to the registration portal.
- The portal validates it and returns the IRN and a signed QR code.
- Print or share the invoice carrying the IRN and QR code.
- If it is rejected, read the reason before retrying — the usual causes are a missing HSN, an invalid GSTIN, a place-of-supply mismatch or a duplicate invoice number.
Cancellation, amendment and getting it wrong
A registered invoice cannot be edited. It can be cancelled within a limited window after registration, and after that the only route is a credit note referencing it.
That makes the check-before-you-register habit worth building. In practice it means reviewing the party, the place of supply and the totals on screen before generating, rather than after the customer queries it.
It also means your invoice numbering has to be right first time: a cancelled IRN does not release the invoice number for reuse.
If e-invoicing does not apply to you yet
Bill as though it might. The turnover threshold has only ever moved in one direction, and the work involved in being ready is work worth doing anyway: complete GSTINs, HSN on every line, place of supply derived rather than typed.
A business already billing that way flips a switch when the threshold reaches it. A business that is not spends a fortnight cleaning masters under a deadline.
The free plan produces invoices with all of those fields, which makes it a reasonable place to build the habit. Start free now.
Invoice numbering: one unbroken series per year
The invoice number has to be consecutive, unique within the financial year, and no more than sixteen characters of letters, numbers, slashes and hyphens. Gaps invite questions. Duplicates cause them.
This is the single most common reason a spreadsheet-based billing setup fails an audit: two people billing on two machines, both starting from the last number they remember. A system that issues the number centrally cannot make that mistake.
The series restarts on 1 April, and Billixo restarts it for you rather than waiting to be told.
Credit notes, debit notes, and fixing a wrong invoice
An issued tax invoice is not something to edit. If the value was too high, or goods came back, the correction is a credit note that references the original invoice. If it was too low, a debit note. Both carry their own numbers and both appear in your return.
There is a deadline on the credit note that matters: the adjustment has to be declared by the return for the relevant month of the following financial year, or by the annual return, whichever comes first. Past that, the note exists commercially but the tax cannot be adjusted.
Software that lets you quietly retype an invoice raised last month is not doing you a favour.
Bill scanning, in practice
The single largest time cost in most small businesses is not raising invoices — it is entering purchases. A photograph of a supplier bill goes in and a structured draft comes out: supplier, GSTIN, line items, rates, tax split and total.
You check it. That is the workflow, and it is deliberate: an extraction you did not read is a liability, not a saving. But checking a filled form takes fifteen seconds and typing one takes three minutes, and that difference compounds over a month of purchases.
Who it is built for
Small and mid-sized Indian businesses that are registered under GST and bill regularly. One person doing everything, or a counter with three people billing at once and an accountant who needs the month to close cleanly.
The design assumption throughout is that whoever raises the invoice is busy and is not a tax specialist. So the tax is computed rather than asked for, the compliance fields are populated rather than presented as questions, and the report the accountant wants is a download rather than a request.
Try it free — the free plan needs no card and does not expire.
What "free" means here, exactly
The Free plan costs nothing, needs no card, and has no expiry date. It is not a trial that turns into a bill; it is a plan you can run a small business on indefinitely.
What it gives you:
- Real GST invoices with the full Rule 46 field set
- Customers and products, with HSN/SAC held against each
- A daily and monthly invoice allowance, generous enough for a small operation
- One login
- Export of your own data, whenever you want it
What it does not give you:
- A watermark-free PDF
- GSTR-1 and GSTR-3B export
- The AI features — bill scanning, HSN lookup, the assistant
- Extra team logins, bulk import, recurring invoices and reminders
Every new account also gets the full paid feature set for its first 14 days, so you can see what the ceiling looks like before deciding whether you need it. When that ends nothing is charged and nothing is deleted — the account simply settles onto Free.
Start free now — it takes an email address and about a minute.
Reliability, backups and getting your data out
Cloud billing software is only as good as its worst day. Two things matter more than any feature list: that your data is backed up somewhere you can reach, and that you can export it in a format something else can read.
Exports here are CSV, Excel and JSON, on every plan including the free one, covering customers, products, invoices and payments. That is the honest test of whether software respects you — not what it promises, but what it lets you take when you leave.
Frequently asked questions
Who does e-invoicing apply to?
It applies above an aggregate turnover threshold that has been lowered in stages since introduction. Because it has changed more than once, check the current notification or the portal rather than relying on any article for the figure.
What is an IRN?
The Invoice Reference Number returned by the invoice registration portal when it accepts your invoice. It comes with a digitally signed QR code, and both must appear on the invoice you give the customer.
Can I edit an e-invoice after generating it?
No. It can be cancelled within a limited window after registration; after that a credit note referencing the original is the only correction route.
Can I move my existing customers and products in?
Yes. Bulk import from CSV or Excel on any paid plan, and export back out in CSV, Excel or JSON at any time, including on Free. Most people bring their party and item lists across in one pass and carry outstanding invoices as opening balances.
Will my accountant be able to work with it?
That is what the GSTR-1 and GSTR-3B summaries are for. They export in formats a practitioner can open and reconcile without repairing the file first — which, in practice, is most of what a CA wants from a client’s billing software.
Try it — the demo is the product
There is no sales call and no scheduled demo, because a recorded walkthrough of somebody else’s data tells you nothing about your own. Open an account instead and raise a real invoice for a real customer; it takes about a minute and costs nothing.
Open the software demo → — sign in, or create a free account from the same screen.
See full details on the home page → — features, the AI, pricing and the answers to the usual questions.
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