Singapore has ushered in a new era of digital tax with the national GST e-invoicing regulation. From November 2025, businesses that are GST-registered will have to transmit their e-invoice data directly to the Inland Revenue Authority of Singapore (IRAS) over InvoiceNow, which runs on the worldwide Peppol network.
Knowing how to upload e-Invoices to the IRAS portal is crucial for every Singapore business that wants to remain compliant and efficient. This post by Advintek, a trusted Peppol-ready e-invoicing solutions provider, describes how business users can get ready and onboard to InvoiceNow and conveniently submit their e-invoice data to IRAS, while ensuring that all requirements are met and details accurate.
What Is e-Invoicing in Singapore?
InvoiceNow is Singapore’s national e-invoicing network under the nationwide digitalisation agenda by the IMDA and IRAS.
Under this e-invoice format, all GST-registered businesses would have to send their invoice details to IRAS via Peppol-compliant software that are developed based on the InvoiceNow standard.
It’s data communication structure is replacing the manual or pdf based submissions and it relieves you from validation and recording of your invoice at the end so that tax authority do it for you automatically.
Objectives of the e-Invoicing Mandate:
- Improve GST compliance and accuracy
- Simplify B2B invoicing and accounting tasks
- Eliminate manual, niedata data entry and human errors
- Enhance interoperability across business systems
- Harmonise Singapore with the global e-invoicing guidelines or standards
Timeline of the e-Invoicing Mandate
Phase-wise upgradation of the IRAS mandate will enable smooth transition:
- May 1, 2025: Open to a wider audience.
- November 1, 2025: All new entities taking registration voluntarily under GST to remain eligible for e-invoicing.
- April 1, 2026: This requirement applies to all new voluntary GST registrants, regardless of when they were incorporated.
Although pre-informed of such rules, no existing GST-registered entities are so far told to comply but encouraged to do so prior implementation pause date else they might face subsequent disturbances and other transitions.
The Role of InvoiceNow and Peppol
In order to learn how e-invoice submissions function, we must first differentiate between InvoiceNow and Peppol — two closely-tied systems that serve as the backbone of Singapore’s e-invoicing system.
InvoiceNow
InvoiceNow is the IMDA-managed nationwide e-invoicing network in Singapore. It allows companies to exchange structured electronic invoices directly between their financial systems in a secure and standardised digital format.
Retailers and vendors on InvoiceNow can automate the sending of invoices between trading partners — and now can also send invoice information to IRAS at regular intervals for GST reporting.
Peppol (Pan-European Public Procurement Online)
InvoiceNow is driven by Peppol, the world standard. This guarantees that the e-invoice is formatted as well as sent in a uniform way, thereby making it compatible with other systems, nations and sectors.
With Peppol, Singapore based organisations are not only able to be IRAS compliant but can send/receive invoices with global partners on the same network.
Understanding Access Points (APs)
All companies have to be connected with the Peppol network via an Access Point (AP) – a gateway that sends and receives e-invoices safely.
APs ensure that invoices are verified, formatted correctly and delivered to the correct recipients (including IRAS).
We integrate with Peppol certified Access Points (APs) so you can be connected without any manual steps – from your accounting system to the InvoiceNow network, and subsequently the IRAS portal.
What is the mandate for e-Invoice Submission to IRAS?
For businesses to send e-invoices to IRAS, they need:
- Adopt an InvoiceNow-enabled solution – IMDA pre-approved applications that are plugged into the Peppol network.
- Be listed on the Peppol Directory — with an active Peppol ID.
- The invoice shall contain all Mandatory Data Elements (MDEs).
- Submit invoice information to IRAS through an Access Point (AP) by the due dates.
Advintek’s e-invoicing solution is developed in a way that fulfills all these requirements. It guarantees that a submission contains the required data items, it is validated and securely transmitted to IRAS.
When to Submit e-Invoices to IRAS
You must submit your invoice data by the earlier of:
- The date your GST return is filed, or
- The official due date for that GST period.
Example:
If your GST period runs from 1 January to 31 March and you file your return on 20 April, then you must send your e-invoice data to IRAS by 20 April.
If you haven’t filed your return yet, the deadline defaults to 30 April — the official due date.
Advintek’s automation makes sure you never miss these deadlines by monitoring submission timelines and alerting you when it’s time to file.
Step-by-Step Process: How to Submit e-Invoices to the IRAS Portal
Below is a detailed guide to help you navigate the submission process using Advintek’s Peppol-ready e-invoicing solution.
Step 1: Ensure InvoiceNow Enablement
- Confirm that your current accounting or ERP system supports InvoiceNow.
- If it doesn’t, Advintek can either integrate with your existing setup or onboard you directly onto their Peppol-ready e-invoicing platform.
- You’ll also need to register your business on the SG Peppol Directory and obtain a valid Peppol ID.
Step 2: Connect to a Peppol Access Point (AP)
- Collaborate with Advintek to establish a connection with an IMDA-certified Access Point.
- This connection ensures your invoice data is transmitted securely to IRAS via the InvoiceNow network.
Step 3: Generate Structured e-Invoices
- Use either your accounting software or Advintek’s platform to create invoices.
- The system will automatically generate PINT SG-compliant e-invoices that include all the Mandatory Data Elements (MDEs) required by IRAS.
Step 4: Submit Invoice Information to IRAS
- After the invoices are verified, the validated invoices journey through the Peppol network to IRAS via your Access Point.
- All submissions are transmitted and encrypted to maintain data integrity.
Step 5: Acknowledgement and Acceptance of Order
- If submitted successfully, IRAS will issue an acknowledgment of receipt.
- Advintek automatically captures those acknowledgments for auditing and compliance reasons.
Step 6: Check and Submit – Monitor Your Submission
- With Advintek’s centralized dashboard, monitor each submission, track down bad records and re-submit modified data.
- This assists with ensuring all of your GST filing requirements are completed, accurate and kept up to date.
Different Types of e-Invoice Submissions to IRAS
Depending on the nature of the transaction and whether your trading partners are on the InvoiceNow network, different submission types apply:
| Type | Scenario | Description |
| Type 1A: Peppol Invoice Submissions | B2B transactions where both supplier and customer are on InvoiceNow | Invoices transmitted automatically through Peppol to both the buyer and IRAS |
| Type 1B: Solution-Extracted Invoice Submissions | Purchases from Peppol-registered suppliers | The buyer’s system extracts purchase data and sends it to IRAS |
| Type 2: Non-InvoiceNow Sales Submissions | Sales to non-registered customers or via POS | Supplier records data in an InvoiceNow solution, which generates and sends it to IRAS |
| Type 3: Non-InvoiceNow Purchase Submissions | Purchases from non-Peppol suppliers or petty expenses | Buyer records and submits extracted invoice data to IRAS |
Advintek automates all four submission types, ensuring consistency and compliance across all transaction types.
Mandatory Data Elements (MDEs)
IRAS requires specific data fields in every e-invoice submission. Missing or incorrect fields can lead to rejection.
Supplier Details:
- Supplier Name
- Unique Entity Number (UEN)
- Business Address (including postal code and country)
- GST Registration Number
Customer Details:
- Customer Name
- Customer UEN (if applicable)
- Address
Invoice Details:
- Invoice Number
- Issue Date
- Type Code (e.g., standard invoice, credit note)
- Currency Code
- Total Invoice Amount (with and without GST)
- Amount Due
Tax Details:
- GST Category Code (SR, ZR, etc.)
- GST Rate (e.g., 9%)
- Taxable Amount
- GST Amount
Advintek’s validation engine checks all these fields before submission to ensure IRAS acceptance on the first attempt.
Best Practices for Smooth e-Invoice Submission
- Test early – Submit pilot e-submissions prior to the mandate to discover potential system inadequacies, confirm workflows and verify that there is successful transfer of data with IRAS.
- Keep your data clean — Keep up-to-date UENs and GST–transfer pricing values for customers or suppliers consistently matched throughout the invoicing system to avoid having invoices rejected, or compliance held up.
- Automate as much as possible – Minimize man-made errors with integrated solutions that auto-check the invoice fields, GST rules, and further integrate to your accounting software.
- Track confirmations status — Ensure no submission goes unverified with IRAS acknowledgments, identify mail delivery responses and rapidly address any denied or pending invoices to keep things moving.
- Keep files – Keep all invoices and submission information safe in encrypted cloud storage or HIPAA compliant document management systems, just as you would any record that might be audited (minimum of 5 years).
- Stay informed — Monitor IRAS and IMDA announcements for standard changes, schema updates or new technical requirements to ensure ongoing compliance.
Advintek automatically updates compliance modules as IRAS or IMDA release new specifications, ensuring your business remains compliant without extra effort.
Conclusion
The impending GST e-invoicing is a significant leap for Singapore’s digital compliance by IRAS. With InvoiceNow and Peppol connectors, companies are able to streamline GST reporting, save time on manual admin tasks as well as minimise errors in tax filing.
What Advintek does is to make it easy for you to get, and stay, compliant. Leveraging our InvoiceNow-ready, Peppol-ready and IRAS-compliant e-invoicing networks platform, you can remove your invoice generation, transmission and reporting from the manual hands process while guaranteeing complete data accuracy and protection with business identity.
Get ahead of the November 2025 deadline – get Advintek’s e-invoicing solution today and submit your IRAS e-invoice smoothly with ease.
