At a minimum, invoicing software generates, sends, and tracks bills. But some tools can also connect billing directly to payment collection, follow up on overdue invoices, handle multicurrency transactions, and keep your accounts reconciled, largely without manual input. As the Inland Revenue Authority of Singapore (IRAS) begins to roll out mandatory e-invoicing requirements, Singapore businesses should consider invoicing software that both meets requirements and improves cash flow and efficiency.

Below, we’ll explore how invoicing software can reduce days sales outstanding (DSO), how a single billing workflow can handle both PayNow and international card payments, and what the InvoiceNow requirement means for your business.

Highlights

• Invoicing software can decrease DSO by automating payment reminders, offering multiple payment methods, and making it easier for clients to pay.

• Many Singapore businesses need software that handles both domestic transfers and multicurrency international payments within a single workflow.

• New voluntary registrants for goods and services tax (GST) must use InvoiceNow-compliant software. This mandate will extend to all GST-registered businesses by 2031.

What is invoicing software?

Invoicing software generates, sends, and tracks bills. For Singapore businesses, it can generate compliant invoices for GST (each with the correct registration number, tax rate, and itemized list), then deliver them instantly and allow businesses to receive payment without manually matching a transfer to every spreadsheet line item.

How does invoicing software reduce DSO for Singapore businesses?

DSO is the average number of days between when a business issues an invoice and when it receives payment. A business that offers net 30 terms but consistently gets paid in 45 days has a DSO problem.

Here’s how invoicing software can help:

• Faster delivery: Manually emailed PDFs can end up buried in your client’s inbox or in a spam folder. A digital invoice is quicker to open for a client who’s already working on their computer, and embedded payment links are faster for your client than manual bank transfers.

• Automated reminders: Invoicing software can send reminders automatically according to a configurable sequence (e.g., a reminder three days before payment is due, another on the due date, a follow-up the week after). Research has shown that businesses that automate their payment acceptance processes get paid faster.

• Multiple payment options: Make paying easier for your clients by offering fast payments. Offering PayNow alongside card payments means a client in Singapore can pay you quickly from their banking app, while an Australian client can pay by card.

• Real-time visibility: The software can show exactly which invoices are open and for how long. If you’re not sending automatic reminders, this can expedite your manual follow-up and prevent you from sending the same collection email to everyone.

What features should Singapore businesses look for in invoicing software?

Different invoicing tools offer different features. The right software for businesses in Singapore is one that can handle GST compliance, local payment methods, cross-border billing, and accounting software integration.

Here’s what you should look for:

• GST compliance and InvoiceNow readiness: Your software needs to generate invoices that meet IRAS's format requirements. They have to include the correct GST registration number, the relevant tax rates, and itemized tax amounts. From 2026 onward, new voluntary GST registrants will also need software that can transmit invoices via the Peppol network.

• PayNow integration: PayNow is a popular transfer method for B2B and B2C transactions in Singapore. Find software that can generate a PayNow quick-response (QR) code or a link directly on your invoice.

• Multicurrency billing: If you bill clients in Australia, the US, or anywhere else in the region, you’ll need invoices that display prices and accept payments in the clients’ currencies. They must also reconcile correctly in Singapore dollars (SGD) on your end.

• Accounting software integration: Invoicing software that syncs with your accounting software updates your accounts automatically.

How does the IRAS GST InvoiceNow requirement affect Singapore businesses?

InvoiceNow is Singapore's national e-invoicing framework. It’s built on the international Peppol standard, which allows businesses to transmit structured digital invoice data directly between accounting systems. IRAS is making InvoiceNow mandatory in stages. If you're registered for GST, your invoicing software will soon need to generate invoices in the Peppol format and transmit them through the network.

As of April 1, 2026, InvoiceNow is mandatory for all new voluntary GST registrants. From 2028–2031, a phased rollout will continue for new compulsory GST registrants and existing GST-registered businesses. Those with annual supplies less than or equal to 200,000 SGD will come first, while bigger businesses will have more time.

How can Singapore businesses implement compliant invoicing software?

The April 2026 deadline applies only to businesses that voluntarily register for GST. But it’s a good reason for all small and medium-size enterprises (SMEs) in Singapore to assess their current setups.

• Check your GST status and timeline: If you're already registered for GST, identify which revenue tier you'll fall into for the 2028–2031 rollout. If you're currently approaching the 200,000 SGD threshold, factor InvoiceNow compliance into your future plans.

• Confirm your software is Peppol compliant: The IRAS website maintains an updated list of compliant vendors. Before you commit to a tool or choose a new one, ensure it’s on the list.

• Access transitional funding: GST-registered SMEs can access a grant of up to $1,000 SGD to offset onboarding costs for InvoiceNow-compliant software.

You don’t have to change everything overnight. Start by routing new clients through the new system and continue managing existing recurring invoices through your current setup. Many platforms let you import client and product data, which makes onboarding faster and easier.

How Stripe Invoicing can help

Stripe Invoicing simplifies your accounts receivable (AR) process—from invoice creation to payment collection. Whether you’re managing one-time or recurring billing, Stripe helps businesses get paid faster and streamline operations:

• Automate AR: Easily create, customize, and send professional invoices—no coding required. Stripe automatically tracks invoice status, sends payment reminders, and processes refunds, helping you stay on top of your cash flow.

• Accelerate cash flow: Reduce DSO and get paid faster with integrated global payments, automatic reminders, and AI-powered dunning tools that help you recover more revenue.

• Enhance the customer experience: Deliver a modern payment experience with support for 25+ languages, 135+ currencies, and 100+ payment methods. Invoices are easy to access and pay through a self-serve customer portal.

• Reduce back-office workload: Generate invoices in minutes and reduce time spent on collections through automatic reminders and a Stripe-hosted invoice payment page.

• Integrate with your existing systems: Stripe Invoicing integrates with popular accounting and enterprise resource planning (ERP) software, helping you keep systems in sync and reduce manual data entry.

Learn more about how Stripe can simplify your AR process, or get started today.