GST InvoiceNow for accountants and bookkeepers: Get every client ready

Published Tuesday 27 October 2026

Table of contents

• GST InvoiceNow timeline at a glance
• How to sort your client list by phase and turnover band
• InvoiceNow readiness checklist for each client
• How to connect a client to Invoici from Xero
• Get your clients InvoiceNow-ready with Xero
• FAQs on GST InvoiceNow for accountants and bookkeepers

Key takeaways

• Voluntary goods and services tax (GST) registrants are already in scope, and existing registrants follow announced phases running 2028–2031.
• Sorting your client list by registration type and turnover band helps you plan team capacity and give each client a specific date.
• Check each client's GST registration, base currency, Peppol ID, and CorpPass access before you connect them to Invoici from Xero.
• Joining the Peppol network and turning on submission to the Inland Revenue Authority of Singapore (IRAS) are two separate steps.

GST InvoiceNow timeline at a glance

The GST InvoiceNow requirement asks GST-registered businesses to send invoice data to IRAS through InvoiceNow, Singapore's Peppol-based e-invoicing network. IRAS sets out the phased rollout on its GST InvoiceNow requirement page, last updated 8 October 2026.

Here's how IRAS brings businesses in:

• from 1 November 2025, companies that register for GST voluntarily within six months of incorporation
• from 1 April 2026, anyone applying for voluntary GST registration, whatever their business structure or incorporation date
• from 1 April 2028, businesses applying for compulsory registration, plus existing registrants with total annual supplies of S$200,000 or less
• from 1 April 2029, existing registrants with supplies of S$1,000,000 or less
• from 1 April 2030, existing registrants with supplies of S$4,000,000 or less
• from 1 April 2031, existing registrants with supplies above S$4,000,000

An existing client's band comes from total supplies (Box 4 of the GST return) in accounting periods ending in calendar year 2025. That's set out in the IRAS e-Tax Guide on the requirement, which also says legislation for the 2028–2031 phases will be enacted later. Treat those later dates as announced by IRAS and keep an eye on updates.

IRAS has been notifying businesses registered before 2026 of their implementation dates since mid-2026. Clients without a notice, such as those with no GST returns for periods ending in 2025, will hear later. For what this means inside Xero, see Xero's overview of the requirement.

How to sort your client list by phase and turnover band

A phase-sorted client list shows you when each onboarding wave lands, so you can plan staff time well ahead. It also gives each client a conversation about their own date.

Work through these steps in your practice management system or a shared spreadsheet:

1. Export every GST-registered client from your practice records.
2. Tag each client's registration type, voluntary or compulsory, along with the registration date.
3. Pull each client's 2025 Box 4 total supplies and assign a band: S$200,000 or less, S$1,000,000 or less, S$4,000,000 or less, or above S$4,000,000.
4. Record the implementation date from the client's IRAS notice, which overrides any date you've inferred from the band.
5. Flag any client without an IRAS notice as "date to be confirmed".
6. Mark excluded entities: overseas vendors under the overseas vendor registration (OVR) regime and businesses registered only because of reverse charge.
7. Order your onboarding queue and assign staff by phase.

Keep the exclusions tight: a foreign company with a Singapore branch is still in scope. For a client with less than a full year of 2025 periods, the e-Tax Guide lets you extrapolate supplies to a 365-day equivalent.

Say a café client reported S$850,000 in Box 4 for 2025 and hasn't had a notice yet. Plan for the 1 April 2029 phase, then swap in the IRAS date once it arrives. Across your whole list, the same view shows where work clusters, such as a group of smaller clients due in April 2028.

InvoiceNow readiness checklist for each client

Once a client has a phase, run them through this checklist before you book the connection. It covers setup you can confirm in Xero and data the client needs to gather.

• Confirm the GST registration type and date. For voluntary registrants in the 2025 and 2026 phases, InvoiceNow is a registration condition, and IRAS may revoke registration for non-compliance.
• Check the Xero organisation's base currency, and confirm any organisation with a base currency other than Singapore dollars (SGD) with Xero support before go-live.
• Review how the client invoices in foreign currencies. Each invoice needs SGD tax totals converted at IRAS-approved exchange rates.
• Prepare the client's Peppol registration. Their Peppol ID is 0195:SGUEN followed by their Unique Entity Number (UEN), and each Xero organisation takes one UEN.
• Book time with the client's CorpPass administrator. They'll need to authorise the registration, so schedule them for your connection session.
• Collect Peppol IDs for key suppliers and customers. Search the SG Peppol Directory and update each contact in Xero.
• Map invoices that sit outside the network. Data for these, and for credit notes, still goes to IRAS by the earlier of the return's filing date or due date.

Inside your practice, a completed checklist becomes the hand-off note for whoever runs the connection. For the client, it's a short to-do list, such as CorpPass access and their top customers' Peppol IDs.

How to connect a client to Invoici from Xero

Xero (Singapore) Pte. Ltd. is on the Infocomm Media Development Authority (IMDA) list of InvoiceNow-Ready Solution Providers, dated 12 October 2026. Clients connect through Invoici from Xero, and e-invoicing needs a paid subscription because it's excluded from the free trial.

1. Open Invoici from Xero on the Xero App Store

Find Invoici from Xero on the Xero App Store and choose to sign up with Xero. The app then connects to the client's tax rates, invoices, currencies, and contacts.

2. Confirm the UEN and business details

The client's Peppol ID is built from their UEN, so match it to the number on your readiness checklist. Check the business name and details at the same time.

3. Get the CorpPass administrator to authorise

The client's CorpPass administrator approves the registration to complete the connection. If you've booked them in advance, this happens in the same session.

4. Record the Peppol ID and Invoici email address

Once registration completes, Invoici from Xero returns the client's Peppol ID and an Invoici email address. Save both in your client file and share the Peppol ID with the client's customers and suppliers.

E-invoices sent with Xero's e-invoicing tools go to recipients within Singapore. Raise this early with clients who export.

5. Turn on IRAS submission for the GST InvoiceNow requirement

Activate IRAS submission as its own step, because joining the Peppol network alone doesn't meet the requirement. Confirm the current steps on Xero Central before you walk a client through them.

Get your clients InvoiceNow-ready with Xero

With a phase-sorted list and a checklist for every client, your clients get a confirmed date and a working connection well ahead of their phase. Your practice gets a predictable onboarding workload in return.

Join the partner program to get Xero support as you build InvoiceNow readiness into your services. For more ideas on running your practice, browse Xero's guides for accountants and bookkeepers.

FAQs on GST InvoiceNow for accountants and bookkeepers

These frequently asked questions cover points you might raise when moving clients onto InvoiceNow.

Can you register clients for InvoiceNow on their behalf?

Yes, Xero lets advisors register business clients. The client's CorpPass administrator still authorises the registration, so plan the session around their availability.

What happens with customers who aren't on InvoiceNow?

Your client still submits that invoice data to IRAS, extracted from their accounting solution. If any line on an invoice or credit note falls within the requirement, the whole document's data goes to IRAS.

What if a client hasn't received an IRAS notification?

IRAS will confirm their date later, so plan from the client's 2025 Box 4 band in the meantime. IRAS also links an implementation date calculator from its InvoiceNow page that you can use as a cross-check.

Does InvoiceNow cover purchases as well as sales?

Yes, purchase invoice data reported in the GST return is in scope alongside sales. Partially exempt businesses submit all purchase invoice data with GST incurred, except disallowed expenses, whether or not they claim the input tax.

Is there funding to help clients with the cost?

IRAS lists a GST InvoiceNow Transition Grant of S$1,000 for eligible small and medium-sized enterprises (SMEs) with supplies of S$4,000,000 or less. Check current eligibility on the IRAS InvoiceNow page before you raise it with clients.

How long should clients keep InvoiceNow records?

IRAS expects clients to keep records for at least five years. Where invoice data and the GST return differ for legitimate reasons, clients won't be penalised if they can produce those records on request.