e-Invoicing in Singapore: Key Deadlines, Requirements & Compliance Guide
Singapore is shifting to structured e-invoicing with InvoiceNow, the nationwide Peppol-based network. From 1 November 2025, new voluntary GST registrants must adopt InvoiceNow, and from 1 April 2026, it becomes mandatory for all new voluntary GST registrants. So, you need to be prepared for this transition. This InvoiceNow Singapore guide covers everything you need to know to stay compliant and ready for e-invoicing in Singapore.
What is e-Invoicing in Singapore?
An e-Invoice in Singapore is a digital invoice sent through InvoiceNow, the nationwide e-invoicing network based on the Peppol standard. With InvoiceNow, businesses send structured invoice data directly from one accounting system to another system.
NOTE - Invoices in paper or PDF format sent via email are not considered e-invoices.
Timeline for e-Invoicing in Singapore
GST-registered businesses must use Singapore e-invoicing solutions to submit invoice data to IRAS. This will be implemented in phases, starting with new voluntary GST registrants. A soft launch on 1 May 2025 will allow existing GST-registered businesses to begin transmission through the InvoiceNow network.
Date Requirement
1 May 2025 Soft launch: Existing GST-registered businesses can start using InvoiceNow voluntarily.
1 November 2025 Mandatory for newly incorporated companies that register for GST voluntarily.
1 April 2026 Mandatory for all new voluntary GST registrants, regardless of incorporation date or business type.
How InvoiceNow Works
The 5-Corner Model Explained
InvoiceNow operates using a 5-corner model, an extension of the Peppol 4-corner model, with IRAS acting as the fifth corner to receive invoice data for tax reporting.
1. Supplier’s Accounting System (Corner 1) – The supplier creates an invoice using an InvoiceNow-enabled system.
2. Supplier’s Access Point (Corner 2) – The invoice is converted into the Peppol standard format and sent through the network.
3. Customer’s Access Point (Corner 3) – The invoice is securely transmitted to the customer’s Access Point.
4. Customer’s Accounting System (Corner 4) – The customer receives the invoice in their system for processing.
5. IRAS (Corner 5) – A copy of the invoice data is automatically transmitted to IRAS via API for tax reporting and compliance.
This model ensures seamless invoicing between businesses while allowing IRAS to receive real-time invoice data for GST monitoring and compliance.
Types of Submissions
Businesses must submit invoice data to IRAS through InvoiceNow using the following submission types:
Type 1A: Sales Within the InvoiceNow Network
• A GST-registered supplier issues an invoice to a customer who is also on the InvoiceNow network.
• The invoice is sent through the supplier’s Access Point and transmitted to the customer.
• The supplier’s Access Point forwards a copy of the invoice data to IRAS automatically.
Type 1B: Purchases Within the InvoiceNow Network
• A GST-registered customer receives an invoice through the InvoiceNow network.
• The invoice is recorded in the customer’s InvoiceNow system.
• The customer’s system extracts the invoice data and transmits it to IRAS via its Access Point.
Type 2: Sales Outside the InvoiceNow Network
• A supplier issues a paper or PDF invoice to a customer who is not on the InvoiceNow network.
• The invoice is recorded in the supplier’s accounting system.
• The supplier’s system extracts the invoice data and transmits it to IRAS via its Access Point.
Type 3: Purchases Outside the InvoiceNow Network
• A customer receives a paper or PDF invoice from a supplier who is not on the InvoiceNow network.
• The invoice is recorded in the customer’s accounting system.
• The customer’s system extracts the invoice data and transmits it to IRAS via its Access Point.
How Data is Transmitted to IRAS via Access Point Providers
Businesses connected to InvoiceNow do not need manually report invoices to IRAS. Once an invoice is issued or recorded:
1. The InvoiceNow system validates the invoice data to check for missing information.
2. It verifies the supplier’s GST registration to prevent incorrect GST charges.
3. The invoice data is automatically sent to IRAS via API through the Access Point.
This automated process reduces compliance efforts, improves GST accuracy, and helps businesses meet tax requirements with minimal manual intervention.
Scope of GST InvoiceNow
The GST InvoiceNow Requirement applies to GST-registered businesses for specific transactions. Businesses must ensure that invoice data related to these transactions is transmitted to IRAS in accordance with the requirement.
Transactions Covered
GST-registered businesses must transmit invoice data for the following:
• Standard-rated supplies – Local sales of goods and provision of services subject to GST at the prevailing rate.
• Zero-rated supplies – Export sales of goods and provision of international services where invoices are issued.
• Standard-rated purchases – Local purchases from GST-registered suppliers where input tax is claimed or will be claimed, excluding purchases subject to Reverse Charge.
Businesses Excluded from the GST InvoiceNow Requirement
The following businesses are excluded from the requirement:
• Overseas entities – Entities that belong outside Singapore for GST purposes, including those registered under the Overseas Vendor Registration (OVR) regime.
• Businesses registered under the Reverse Charge regime – Entities registered for GST under the Reverse Charge regime are not required to transmit invoice data for such purchases.
Due Date for Transmission
Invoice data must be sent to IRAS by the earlier of:
• The filing due date of the GST return, or
• The actual date the GST return is filed.
Businesses aggregating invoice data should align transmission with their GST return filing cycle.
How is GST InvoiceNow Different from Current Invoicing?
GST InvoiceNow introduces a structured approach to invoice data transmission by leveraging the InvoiceNow network for direct submission to IRAS, unlike traditional invoicing methods.
1. Direct Transmission of Invoice Data to IRAS
Currently, businesses generate invoices and manually report GST transactions in their GST returns. With GST InvoiceNow, invoice data is automatically transmitted to IRAS through the InvoiceNow network via API technology, reducing manual reporting efforts.
2. Standardised e-Invoicing Format
Traditional invoicing often involves paper or PDF invoices, requiring manual entry into accounting systems. Under GST InvoiceNow, invoices are structured using the Peppol e-invoicing standard, enabling seamless machine-to-machine transmission with minimal human intervention.
3. Reduced Errors and Improved Compliance
Manual invoicing processes can lead to errors in data entry and GST calculations. GST InvoiceNow validates invoices at the point of transmission, minimising discrepancies and ensuring compliance with GST regulations. Additionally, businesses can leverage built-in checks to detect wrongful GST charges from non-GST registered suppliers.
4. Faster Reconciliation and Audit Efficiency
Under the current process, businesses must extract and compile records during audits. With GST InvoiceNow, IRAS receives real-time invoice data, improving risk analysis and reducing the likelihood of businesses being selected for audits. If an audit is required, the process is expected to be shorter and more efficient.
5. Enhanced Cash Flow Management
InvoiceNow facilitates faster invoice processing and payments, as invoices are transmitted directly to customers accounting systems. This improves cash flow and reduces delays compared to conventional invoice submission via email or manual processing.
6. Progressive Adoption for GST-Registered Businesses
The transition to GST InvoiceNow will be phased, starting with newly registered voluntary GST applicants, followed by a broader rollout. Businesses are encouraged to adopt early and integrate InvoiceNow solutions to streamline tax compliance and administrative processes.
Mandatory Requirements for e-Invoicing in Singapore
Businesses that need to comply with the GST InvoiceNow Requirement must follow certain rules for e-invoicing. These include:
1. Use an InvoiceNow Solution
Businesses must use an InvoiceNow solution that connects to the Peppol network. This allows invoices to be sent directly to IRAS. The solution can be accounting software bought from a provider or an in-house system connected through an Access Point Provider (AP).
2. Get a Peppol ID
To send and receive invoices through the InvoiceNow network, businesses must register for a Peppol ID. This can be done through their Solution Provider (SP) or AP, with registration managed by IMDA.
3. Send Invoice Data to IRAS
Businesses must send invoice data to IRAS for certain transactions, such as:
• Standard-rated supplies (local sales of goods and services with GST)
• Zero-rated supplies (exported goods and international services)
• Standard-rated purchases (when GST is claimed or will be claimed)
For transactions from Point-of-Sale (POS) systems or petty cash purchases (PCPs), businesses can combine and send the data in batches instead of individual invoices.
4. Include Mandatory Invoice Details
All invoices sent to IRAS must have key details, such as:
• Supplier and customer information (GST Registration Number (GSTN), UEN)
• Invoice details (invoice number, date, total amount, and tax amount)
• The right GST category codes for different types of transactions
These details must follow the Singapore Peppol BIS 3.0 or SG-PINT Specification.
5. Deadline to Send Invoice Data
Businesses must send invoice data to IRAS by the earlier of:
• The due date of their GST return, or
• The actual date they file their GST return
How Can Businesses Prepare for GST InvoiceNow?
Businesses that need to follow the GST InvoiceNow Requirement should start preparing early to make the transition smooth and easy.
Step 1: Check If Your System Supports InvoiceNow
Businesses should first check if their current accounting or finance software is compatible with InvoiceNow. If their system does not support InvoiceNow, they should look for solutions from IMDA’s approved InvoiceNow providers.
Alternatively, businesses can choose a free InvoiceNow solution with basic features. Large businesses with in-house systems should contact an Access Point Provider (AP) to help them connect to the InvoiceNow network.
Step 2: Register for a Peppol ID
To use InvoiceNow, businesses must get a Peppol ID by registering through their Solution Provider (SP) or AP using their Unique Entity Number (UEN). This registration allows businesses to be listed in the SG Peppol Directory, so they can send and receive invoices digitally.
Step 3: Connect to IRAS via API
Businesses must ensure their InvoiceNow system is connected to IRAS via API so invoices can be sent automatically. This connection allows businesses to submit invoice data to IRAS without manual reporting.
Step 4: Activate the Feature and Start Sending Invoices
Once the InvoiceNow system is set up, businesses must turn on the invoice transmission feature in their accounting software. This activation allows invoices to be sent directly to IRAS.
Businesses should conduct test transactions to check if invoices are sent correctly. It is also important to train your team so they understand how to use the system efficiently.
Step 5: Update Business Processes to Follow the Rules
Businesses must review and update their invoicing process to ensure they follow InvoiceNow’s rules. All invoices must include the Mandatory Data Elements (MDEs) required by IRAS.
If businesses use Point-of-Sale (POS) systems or make petty cash purchases (PCPs), they may choose to combine these transactions before sending data to IRAS. They should also set up error checks to detect incorrect GST charges from suppliers who are not registered for GST.
Common Challenges in Adopting InvoiceNow
Switching to InvoiceNow improves invoicing efficiency, but businesses may face some difficulties when making the transition.
1. System Upgrade Needed
Many businesses use older accounting software that may not support InvoiceNow. To connect to the Peppol network, they may need to upgrade their system or work with an Access Point Provider (AP).
2. Staff Training
Employees will need training on how to use InvoiceNow correctly. Since the system follows structured invoicing rules, staff must also understand GST tax codes and automated data submission to IRAS.
3. Supplier and Customer Adoption
For InvoiceNow to work smoothly, both suppliers and customers need to be on the network. If some businesses still use manual invoicing methods, then companies may need to manage both digital and paper invoices.
4. Data Security and Privacy Concerns
E-invoicing involves sensitive financial data so businesses must ensure their InvoiceNow system is secure to prevent fraud and unauthorized access.
How Flick Network Helps Businesses Adopt InvoiceNow
1. Automated GST Compliance – Flick Network ensures full compliance with IRAS requirements by automatically transmitting invoice data to IRAS through API-based integration, reducing manual reporting efforts and tax errors.
2. Seamless Peppol Integration – Our solution is Peppol-certified, allowing businesses to send and receive invoices digitally in a structured format, ensuring smooth transactions between suppliers and customers.
3. Easy Accounting System Integration – Flick Network works with existing accounting and ERP software, enabling businesses to adopt InvoiceNow without major system changes while improving efficiency and record-keeping.
4. Secure and Scalable – Whether you are an SME or a large enterprise, our cloud-based platform offers secure storage, easy access to invoices, and a scalable solution to support business growth.
5. Dedicated Support and Onboarding – We provide step-by-step guidance for businesses to register for InvoiceNow, obtain a Peppol ID, and integrate the system, ensuring a smooth transition with expert support.
Flick Network helps businesses adopt InvoiceNow Singapore with a Peppol-certified solution that ensures seamless compliance with IRAS. Our platform integrates with existing accounting systems for secure, automated invoice transmission. With expert support and Tax and Treasury solutions, your businesses can simplify compliance and improve efficiency.
Benefits of Using InvoiceNow Solutions
1. Streamlined processes: InvoiceNow solutions enable direct transmission of e-invoices in a structured data format across different finance systems, thereby eliminating manual work involved in sending, receiving, and recording of invoices into systems.
2. Reduced errors and costs: InvoiceNow solutions reduce manual processes, along with errors and rectification costs. With invoice records maintained electronically, such solutions also reduce invoice storage and retrieval costs.
3. Improved cashflow management: InvoiceNow solutions facilitate quicker invoice processing and payment, helping businesses to more effectively manage their cashflow.
4. Better compliance: InvoiceNow solutions support accurate and timely reporting and ensure businesses meet tax and regulatory requirements.
5. Enhanced security: InvoiceNow solutions provide a secure way to transmit invoice data and reduce the risk of fraud and unauthorized alterations.
Frequently Asked Questions (FAQs)
1. Can businesses continue using paper or PDF invoices?
Paper or PDF invoices do not meet the structured format required for Singapore e-invoicing. To comply with InvoiceNow, businesses must use an InvoiceNow-enabled system that connects to the Peppol network for structured invoice transmission to customers and IRAS.
2. Do all GST-registered businesses have to use InvoiceNow?
No. The requirement currently applies only to new voluntary GST registrants from 1 November 2025 (for newly incorporated businesses) and 1 April 2026 (for all new voluntary GST registrants). However, IRAS encourages early adoption to simplify compliance.
3. What happens if my supplier or customer is not using InvoiceNow?
If a supplier or customer is not on InvoiceNow, businesses must record invoices manually in their system. These invoices are classified as solution-extracted invoices and must still be submitted to IRAS.
4. Does InvoiceNow replace GST return filing?
No. Businesses must continue to file GST returns, but InvoiceNow automates invoice submission to IRAS, reducing manual data entry errors and improving tax compliance under Singapore e-invoicing regulations.
5. What happens if an invoice has errors after submission?
If an invoice contains errors, businesses must issue a credit note referencing the incorrect invoice and submit a new, corrected invoice. InvoiceNow helps by validating invoices before submission, reducing common mistakes.
6. How will businesses know if their customers or suppliers are on InvoiceNow?
Businesses can check the SG Peppol Directory, which lists all registered entities using InvoiceNow. Suppliers and customers with a Peppol ID can receive invoices digitally through the network.
7. Can businesses use InvoiceNow for international transactions?
Yes, InvoiceNow supports cross-border e-invoicing using the SG Peppol International (SG-PINT) Specification. However, businesses must ensure their international trading partners are also connected to the Peppol network.