1. What is the GST system?

The GST system is a portal for exchanging e-invoices in India. Once an invoice is sent in the correct format and assigned an IRN and QR code, it is forwarded to the GST system for registration. An approved invoice will be available for the seller and buyer on the GST portal.

2. What is an IRN number?

IRN is an invoice reference number received after correct invoice validation.

4. How to select best e-invoicing solution and provider?

The best solution needs to be fully compliant with Indian requirements, capable of integrating with GST, and able to convert the e-invoice format requested by your partner to JSON. The best provider should have experience in providing similar services in other countries, so you are sure they are exchanging your sensitive data securely, reliably and most of all in line with governments’ requirements.

e-Invoicing in India

India is on the Road to e‑Invoicing

Mandatory e-invoicing is being rolled out in India in stages. In October 2020, it became mandatory for companies with a combined annual turnover exceeding INR 500 crore. Then, starting from January 1, 2021, it was the turn of companies with a turnover of more than INR 100 crore.

On April 1, 2021, the obligation was extended to companies with an annual turnover exceeding INR 50 crore. Then, in 2022, the threshold was lowered twice: first to INR 20 crore (from April 1), and later to taxpayers with a turnover of more than INR 10 crore (from October 1).

From August 1, 2023, the threshold was lowered further to INR 5 crore, which remains the current applicable threshold for mandatory e-invoicing in India.

Conflicting Regulation: A GSTN advisory (November 2024) introduced a time limit. From April 1, 2025, taxpayers with an Annual Aggregate Turnover (AATO) of Rs. 10 crore or more must upload e-invoices to the IRP within 30 days of the invoice date.

As of April 2025, the GSTN portal guidance clarifies that taxpayers above certain AATO thresholds must upload e-invoices to the IRP within 30 calendar days of the invoice date for specific invoice categories. Businesses should verify the applicable time limit with their tax advisor.

E-invoicing process description

In India, the CTC model was implemented based on the mandatory infrastructure of the invoice registration portal (IRP). All companies based in or with branches in India are required to create e-invoices using their own systems and submit them electronically to the Indian registration portal in JSON format for approval.

All invoices receive an invoice reference number (IRN) and a QR code that contains all invoice details. The IRN is issued after a valid invoice has been approved; invoices without an IRN are considered invalid. If this approval process is successful, digitally signed invoices are uploaded to the GST System. The company then receives proof of invoice registration, and the approved invoice is available to the seller and buyer on the GST portal.

Implementation timeline

2022
- April 1, 2022
  GST-registered businesses with an aggregate annual turnover (AATO) of more than 20 crore and carrying out B2B transactions are required to create e-invoices using their systems and submit them electronically to the Indian Registration Portal (IRP).
- October 1, 2022
  Mandatory e-invoicing applies to taxpayers with an aggregate annual turnover (AATO) of more than 10 crores.
2023
- August 1, 2023
  E-invoicing became mandatory for businesses with an aggregate annual turnover (AATO) of Rs 5 crore ($630,000) and more for their B2B transactions.
- November 1, 2023
  E-invoice upload to the Invoice Registration Portal within 30 days of invoice issuing is mandatory for businesses with an aggregate annual turnover (AATO) of Rs 100 crore or more for their B2B transactions.

Why is Comarch the best choice?

We have 20+ years of experience in carrying out various EDI, e-invoicing, and other document exchange projects around the world. In those years, we have successfully connected more than 130,000 entities from over 60 countries.

1. Legal compliance
Full compliance with the latest data exchange regulations and modern data transfer standards
2. Digitization
Applying new technologies and IT solutions in order to streamline workflows and automate activities and procedures
3. Individual approach
Tailor-made solutions based on processes specific to each company – own road map and a suitable pace of changes
4.Security
Highest level of security for all sensitive and important company data

Frequently Asked Questions

1. What is the GST system?
The GST system is a portal for exchanging e-invoices in India. Once an invoice is sent in the correct format and assigned an IRN and QR code, it is forwarded to the GST system for registration. An approved invoice will be available for the seller and buyer on the GST portal.
2. What is an IRN number?
IRN is an invoice reference number received after correct invoice validation.
3. Who is obliged to send e-invoices?
All companies with headquarters or branches on Indian territory with 20 crores and above turnover must create e-invoices using their systems and send them electronically to the Indian Registration Portal in JSON format for validation.
Since October 1, 2022, mandatory electronic invoicing has been applied to taxpayers with a turnover of over INR 10 crore. In January 2023, e-invoicing became mandatory for businesses with a turnover of INR 5 crore ($630,000) and more.
4. How to select best e-invoicing solution and provider?
The best solution needs to be fully compliant with Indian requirements, capable of integrating with GST, and able to convert the e-invoice format requested by your partner to JSON. The best provider should have experience in providing similar services in other countries, so you are sure they are exchanging your sensitive data securely, reliably and most of all in line with governments’ requirements.

Achieve Global e-Invoicing Compliance with Comarch

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