Singapore e-Invoicing Guide

Singapore has taken a pragmatic, phased approach to e-invoicing through its InvoiceNow initiative, built on the Peppol network. What began as an incentive-driven programme focused on government procurement and voluntary GST registrants has now expanded into a full B2B mandate. The COS 2026 announcement confirmed that all GST-registered businesses must adopt InvoiceNow by April 2031, with rollout staged by annual supply threshold.

The InvoiceNow framework uses the PINT SG specification on the Peppol network, with IMDA overseeing the technical infrastructure and IRAS handling the tax compliance aspects. Businesses are identified by their Unique Entity Number (UEN), which serves as the Peppol routing identifier.

Singapore's timeline is incremental but now extends through 2031. B2G registration became mandatory for government suppliers from April 2025. New voluntary GST registrants must adopt InvoiceNow from November 2025, followed by all voluntary GST registrants from April 2026. The COS 2026 announcement then extends the mandate to all remaining GST-registered businesses: new compulsory registrants and businesses with annual supplies up to $200K from April 2028, up to $1M from April 2029, up to $4M from April 2030, and above $4M from April 2031.

Government suppliers must register on the Peppol network and be capable of receiving e-invoices through InvoiceNow. For B2B, the requirements are expanding in phases: new voluntary GST registrants from November 2025, all voluntary GST registrants from April 2026, and then all remaining GST-registered businesses in revenue-based waves from April 2028 through April 2031.

Following the COS 2026 expansion, all GST-registered businesses will eventually face a mandatory e-invoicing obligation by April 2031. Transitional grants of up to $1,000 for SMEs and $5,000 for larger businesses are available to offset onboarding costs. B2C transactions remain outside the framework. The PINT SG specification requires UEN and postal addresses as mandatory fields in compliant invoices.

Singapore uses a post-audit model via the Peppol network. Businesses connect through Peppol Access Points and exchange invoices using the PINT SG specification. There is no government clearance or pre-authorisation. Invoices flow directly between trading partners, and IRAS receives data for audit purposes.

The 5-corner model means businesses interact with the network through their Access Point provider, which handles the technical aspects of sending, receiving, and validating invoices. IMDA provides grants to help SMEs cover the costs of adoption, making the transition financially accessible.

Singapore's penalty framework is focused on government procurement. Non-compliant suppliers risk exclusion from government tenders and may face difficulties maintaining procurement relationships. Since B2B is largely voluntary, there are no broad B2B-specific penalties. The incentive model relies on grants and procurement advantages rather than fines.