Raffles Consulting Services
GST InvoiceNow supplier onboarding should test identity, GST status, Peppol data, invoice exceptions and reconciliation before activation.
GST InvoiceNow supplier onboarding should begin with clean supplier identity and tax data, not a software switch. A business needs to know who issued the invoice, whether GST was charged correctly, which Peppol identifier applies, how credit notes and non-Peppol purchases enter the system and how submitted data will reconcile to its GST return.
Test a small group of real transaction patterns before wider activation. The aim is to find master-data and workflow errors while they are still easy to correct.
Confirm the connection model
IRAS’s current GST InvoiceNow requirement page says off-the-shelf users should choose an IMDA-accredited InvoiceNow-Ready Solution Provider, register in the SG Peppol Directory using the UEN, obtain a Peppol ID and enable the GST submission feature. Businesses with in-house enterprise systems should work with an accredited Access Point Provider.
For this reason, IMDA’s InvoiceNow page explains that the network uses the open Peppol standard. Singapore-registered businesses need Corppass for the provider’s know-your-customer process. Assign a Corppass administrator and provider contact before technical testing begins.
Record the legal entity, UEN, GST registration number, Peppol ID, accounting system, provider, connection owner and activation status. A group with several GST registrations should not treat one Peppol record as proof that every entity is ready.
Build the supplier master from evidence
For each material supplier, keep the registered name, UEN or foreign identifier, GST registration number where relevant, business address, payment details, currency, tax treatment, Peppol ID and usual invoice channel. Record the source and last verification date.
In practice, do not overwrite a supplier name simply because a recent invoice uses a trading name. Preserve the legal identity used for tax and payment checks. Where two entities in a group have similar names, use the UEN and bank-account confirmation to avoid paying or recording the wrong entity.
Assign change controls for bank details, GST status and Peppol identity. A maker can update the master, but a separate reviewer should approve sensitive fields. Keep the old value and reason for change rather than replacing it without history.
Test wrongful GST charging
IRAS notes that InvoiceNow-Ready solutions can include validation checks to detect GST charged by a non-GST-registered supplier. Configure the check, but do not rely on it as the only control. The accounts-payable team should know how to stop an invoice, verify the supplier and obtain a corrected document.
At the same time, use three test cases: a valid local GST-registered supplier, a local supplier that is not GST-registered and a foreign supplier. Confirm how the system treats tax codes, warnings and posting. Keep screenshots or test reports without retaining unnecessary personal data.
If a supplier’s registration status changes, update the effective date. Old invoices and new invoices may need different treatment. A single current-status field without history can misclassify earlier transactions.
Map invoice and credit-note paths
The current IRAS e-Tax Guide covers Peppol invoices, solution-extracted submissions and other transaction types. Draw the actual path for supplier invoices received through InvoiceNow, invoices received outside the network, credit notes, petty cash, imports and self-billed or third-party-issued documents where relevant.
As a result, For each path, identify who reviews the document, when it posts, which data goes to IRAS, how an error is corrected and how the transaction appears in the GST return. Include rejection and duplicate scenarios. A happy-path test cannot show whether a cancelled invoice remains in the submission history.
The official FAQ says solution-extracted invoice data generally must reach IRAS by the earlier of the GST return filing date or the filing due date. Configure monitoring around the company’s filing timetable.
Use a supplier onboarding test sheet
| Test | Expected result | Evidence |
|---|---|---|
| Identity match | Legal name, UEN and payment record identify the same supplier | Approved supplier-master record |
| GST validation | Tax code follows verified registration status and effective date | Validation result and reviewer |
| Peppol receipt | Invoice arrives once with the expected supplier ID | Network and system transaction IDs |
| Credit note | Adjustment links to the original invoice and tax period | Original and adjustment audit trail |
| Reconciliation | Accepted data agrees to the purchase ledger and GST workings | Difference report and resolution |
Select suppliers that expose different risks: high volume, foreign currency, recurring services, credit notes and non-Peppol invoices. Do not choose only the easiest five suppliers. The test set should represent the work that finance actually handles.
Agree how suppliers will be contacted
For example, Send a concise request for the supplier’s legal name, UEN, GST registration details, Peppol ID and intended activation date. Explain the invoice channel and contact for rejected documents. Do not ask suppliers to send passwords, bank tokens or unnecessary identity documents by email.
For a critical supplier that is not ready for InvoiceNow, record the temporary channel and how the invoice will enter the solution-extracted process. The buyer’s own compliance should not depend on an unsupported assumption that every supplier will join at the same time.
Coordinate purchasing and accounts payable. A purchase order with the wrong entity name can carry the error into the invoice, payment and tax record even when the network transmits perfectly.
Reconcile before activation
In addition, compare the supplier master, accounts-payable ledger, InvoiceNow transaction report and GST working for the test period. Classify differences as timing, duplicate, missing transaction, tax-code error, identity error or rejected submission. Assign an owner and close each item.
Keep existing record-retention controls. IRAS states that GST InvoiceNow does not remove the normal requirement to keep business and tax records. Preserve invoices, credit notes, approvals, payment evidence and corrections in the company’s ordinary record system.
The Singapore transfer-pricing workflow remains the tax pillar cornerstone. The GST InvoiceNow date guide identifies the implementation phase, while the GST registration guide covers turnover tests. The Corporate and International Tax Consulting hub lists related guidance.
For this reason, Supplier onboarding is ready when finance can explain which identity was verified, how each transaction enters the system and how errors return to the tax record. A Peppol ID alone does not answer those questions.