E-Invoicing Rules for Digital Marketing Agencies

Most agency owners read the ₹5 crore number, decide it is a problem for later, and move on. That is usually correct — and occasionally very wrong, because of one habit almost every performance agency has: putting the client's ad budget through your own invoice. An agency keeping ₹80 lakh a year in fees can be billing ₹6 crore a year in total, and it is the total that the law measures.

So this post covers three things: when the mandate actually bites, why ad spend is the thing that pushes agencies over the line early, and what changes on the day it applies to you. If you have not read the GST invoice guide first, start there — that post covers the ordinary invoice, this one covers what replaces it.

Who has to issue e-invoices in 2026?

E-invoicing means you cannot simply print a tax invoice any more. You upload the invoice data to a government Invoice Registration Portal, which returns an Invoice Reference Number and a signed QR code. Only then is the document a valid tax invoice. It is not a new tax — it is a change in how the invoice becomes real.

The threshold has been walked down in stages since 2020:

₹5 crore is still the live threshold as of September 2026. A reduction to ₹2 crore has been discussed at GST Council level more than once, but discussion is not notification — until a notification says otherwise, ₹5 crore stands. Plan for the lower number anyway; the direction of travel over six years has been one way only.

Three details that catch people out:

• It is sticky. The test is whether you crossed ₹5 crore in any financial year from 2017-18 onwards. One unusually good year in 2022-23 puts you inside the mandate permanently, even if you have shrunk since.
• It is PAN-level, not GSTIN-level. Turnover across every GSTIN on the same PAN is added together, all-India. Two state registrations do not give you two thresholds.
• It covers B2B and exports, not B2C. Invoices to registered persons, plus exports and supplies to SEZ, need an IRN. Invoices to individuals do not. Credit notes and debit notes are covered too — people forget the credit note and it breaks the chain.

Exemptions exist — banks, insurers and NBFCs, goods transport agencies, passenger transport, multiplex cinema services, SEZ units, government departments and local authorities. Advertising and marketing services are not on that list, so no, there is no clever categorisation that gets an agency out of it.

Why ad spend puts agencies over the line early

Here is the structural point that no general e-invoicing guide will tell you, because it is specific to how agencies bill.

Aggregate turnover under Section 2(6) of the CGST Act is the value of all taxable supplies, exempt supplies, exports and inter-state supplies under one PAN, computed all-India. It is a gross figure, not a profit figure. So if a ₹10 lakh monthly Meta budget goes out on your invoice as part of what you supply, it is ₹10 lakh of turnover — not the ₹1.5 lakh management fee you actually keep.

Run the numbers on a mid-sized performance agency:

Same agency, same work, same money kept. The middle row is inside a compliance regime the other two are not, purely because of how the invoice was drafted. And it does not stop at e-invoicing — the same gross figure inflates your GST liability if you charge 18% on the full amount instead of on your fee.

The fix is Rule 33 of the CGST Rules, the pure agent provision. Get it right and the ad spend is excluded from your value of supply and therefore from turnover. Rule 33 requires all of the following, and "we wrote reimbursement on the invoice" satisfies none of them by itself:

• You pay the third party (Meta, Google) on the recipient's authorisation — put it in the contract, not in a WhatsApp message.
• The payment is separately indicated on your invoice. A single lump sum kills the treatment instantly.
• The procured supply is in addition to the services you supply on your own account — your management fee is a separate line.
• You hold no title to what you procured, do not use it in your own interest, and recover exactly the actual amount. Any markup on ad spend, however small, and you are not a pure agent on that amount.

That last one is the honest catch. Plenty of agencies quietly mark up media buying. That is a legitimate commercial choice — but if you mark it up, it is your supply, it is your turnover, and you should plan for the threshold accordingly rather than hoping the word "reimbursement" does the work. Take this one to your CA with your actual contracts; it is the single highest-value hour of tax advice a performance agency can buy.

What changes on the day it applies to you?

Less than people fear, if your invoicing is already systematic. A lot, if it is a Word template and a numbering habit.

1. Every B2B invoice gets an IRN. Your billing software pushes the invoice to an IRP, which returns the IRN and a signed QR code that must appear on the printed invoice. No IRN, no valid invoice.
2. Invoice numbering becomes unforgiving. The IRP rejects duplicates. The month-end habit of re-issuing "the same invoice with a corrected amount" stops working.
3. Corrections change shape. You can cancel an IRN on the portal within 24 hours, and you cannot cancel it partially. After that window the only clean route is a credit note plus a fresh invoice. Amendments themselves happen in GSTR-1, never on the IRP.
4. GSTR-1 partly fills itself. Reported e-invoices auto-populate into your GSTR-1, which is a genuine time saving — and also means a wrong invoice is wrong in your return by default.
5. A 30-day clock may apply. Taxpayers with annual aggregate turnover of ₹10 crore and above cannot report an invoice, credit note or debit note to an IRP more than 30 days after its date — the portal blocks it. This has applied since 1 April 2025, and it is exactly the rule that punishes agencies which raise invoices in a batch at the end of the quarter.

On the last point: at ₹5 crore you are not yet inside the 30-day rule, but you should behave as if you are. An agency that invoices late already has a cash-flow problem, and we have written about what late invoicing does to collections. Raising the invoice on the 1st, every month, without anyone remembering to, is the fix in both worlds — and it is what recurring billing is for.

What if you ignore it?

The legal position is blunt. Under Rule 48(5), an invoice issued by someone covered by the mandate, in any manner other than through the IRP, shall not be treated as an invoice. It is not a defective invoice. It is not an invoice.

The penalty commonly cited under Section 122(1)(i) of the CGST Act is 100% of the tax due or ₹10,000 per invoice, whichever is higher, with ₹25,000 per invoice for an incorrect one. Whether input credit is automatically denied to your client is more contested — the Act does not spell out automatic denial, and the point gets argued — but that is cold comfort. In practice what happens is far more ordinary and far more expensive: your client's accounts team finds the invoice does not appear correctly, holds the payment while it is "checked", and your ₹3 lakh retainer sits unpaid through a quarter-end.

That is the real reason to care about this before you have to. Compliance failures in a B2B relationship do not usually show up as a notice from a tax officer. They show up as a payment that does not arrive, and a finance contact who now thinks your agency is disorganised.

A readiness checklist you can run this week

1. Compute your real aggregate turnover. All GSTINs on your PAN, all-India, including exports and any spend you bill gross. Check every year back to 2017-18, not just last year.
2. Decide the ad-spend question deliberately. Either restructure to genuine pure agent treatment under Rule 33, with authorisation in the contract and a separate invoice line, or accept the gross turnover and plan for the mandate.
3. Fix your invoice series. One unbroken, machine-generated series per GSTIN per financial year. Do this before an IRP starts rejecting duplicates for you.
4. Get the SAC code and place of supply right now. They are mandatory fields when you go electronic and there is no room to fudge them — the GST invoice post has the codes.
5. Check where your invoices are generated. If that is Word or a spreadsheet, the day the mandate applies is the day you migrate under pressure. Migrate before.
6. Ask your CA about the ₹2 crore proposal. If you are between ₹2 crore and ₹5 crore, you are in the band a future notification would catch first.

None of this is difficult. It is the sort of thing that only becomes painful when the invoice, the delivery record and the payment status live in three different places — which is the state most agencies are in, and the reason we built billing into the same agency workspace that runs the content calendar and the publishing schedule. Whether you are an agency in Mumbai nearing the threshold or one in Bhopal a long way off, the invoice discipline is the same discipline.

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