What InvoiceNow actually requires
InvoiceNow is Singapore's national e-invoicing framework, built on the PEPPOL network. It replaces the PDF invoice sent by email with a structured XML document sent machine-to-machine via a registered PEPPOL access point. The recipient's accounting or ERP system can read and process the invoice automatically, without human data entry.
For your ERP, this means three things: first, it must be able to generate a PEPPOL BIS Billing 3.0 (UBL 2.1) XML document from your invoice data. Second, it must include Singapore-specific required fields that PEPPOL SG mandates — UEN, GST registration, GST-inclusive line amounts, and payment reference. Third, it must be able to submit that XML to a PEPPOL access point, not just export it as a file.
The compliance gap in off-the-shelf ERPs
Most off-the-shelf ERPs have PEPPOL modules, but the implementation quality varies significantly. Common failure modes include: missing UEN field in the XML structure, GST amounts calculated on net rather than gross basis (incorrect for SG), incorrect currency handling for SGD invoices, and access point submission failures that are silently swallowed rather than surfaced as errors.
Manufacturers discover these gaps when a counterpart reports that the invoice was not received via PEPPOL, or when the IRAS access point returns a validation error. At that point, the fix requires either a module update, a configuration change, or a developer engagement — all with urgency.
What a compliant ERP must generate
The minimum required fields for a valid SG PEPPOL invoice: Invoice ID (unique), Issue Date, Due Date, Supplier party (name + UEN + GST registration + address), Customer party (name + UEN or NRIC + address), Invoice lines (description, quantity, unit price, line total, GST rate, GST amount), document-level GST total, and document-level payable amount. Optional but commonly required: PO reference number, delivery address, payment means (bank account for GIRO).
The XML structure must validate against the PEPPOL SG extension of BIS Billing 3.0. Invalid documents are rejected by the access point and not delivered to the recipient — there is no fallback to email.
How custom ERP handles InvoiceNow
A custom ERP built for Singapore manufacturers includes InvoiceNow compliance as a baseline requirement, not an add-on. The invoice generation module produces validated UBL 2.1 XML as part of the standard invoice workflow. Submission to the PEPPOL access point is triggered automatically on invoice approval. Failures are surfaced to the operator with the specific validation error, not silently logged.
The access point connection is handled via one of the IMDA-certified Singapore access point operators. Most custom ERP implementations use Storecove or Peppol.tech for SG SMB use cases. The cost of access point subscription (typically S$50–S$200/month) is separate from the ERP build cost.
The grant angle
Manufacturers who adopt InvoiceNow as part of an ERP implementation may be eligible for both PSG (pre-approved InvoiceNow solutions) and EDG (custom or integrated builds). The PSG pre-approved list includes several accounting software with InvoiceNow connectors, but these are not manufacturing ERPs — they are invoice-only tools. For manufacturers who need InvoiceNow as part of a broader ERP with production planning, procurement, and job costing, EDG is the more appropriate grant.