Thailand runs two voluntary schemes side by side. The full e-Tax Invoice & e-Receipt system is built for companies with an ERP and volume; e-Tax Invoice by Email is built for businesses that have neither. They are separate schemes with different obligations — not a basic and a premium tier of the same thing.
| e-Tax Invoice & e-Receipt | e-Tax Invoice by Email | |
|---|---|---|
| Built for | Companies issuing at volume from an ERP | Smaller VAT registrants without that infrastructure |
| Document format | Structured XML to the ETDA standard | |
| What makes it valid | Digital signature from a Thai licensed certification authority | Time-stamp applied by ETDA’s email service |
| Certificate needed | Yes — and it has to be renewed | No |
| Reporting to the RD | Monthly, by the 15th of the following month | Handled through the ETDA email service |
| Fits an ERP integration | Yes — this is what integrations target | Rarely; it is a manual, per-document route |
Eligibility thresholds and procedures are set by the Revenue Department and have changed over time. Confirm the current rules for your business before registering.
Registration covers both bodies before the first electronic document is issued.
Every document is signed with a certificate from a Thai licensed CA, held by you or by your service provider.
A UBL-derived message standard carrying Thai identifiers: the 13-digit Tax ID and the branch code.
Tax invoices and receipts, plus the debit and credit notes that adjust them — each needing a clean reference back to the original.
The signed document goes to the buyer electronically. There is no clearance step in between.
Documents for the month are reported to the Revenue Department by the 15th of the following month.
The Revenue Department confirms that authorised businesses may still issue in electronic or paper form, across B2B, B2C and B2G. Nothing forces the switch. The case for it is operational: no printing, posting and storing of paper tax invoices, faster buyer processing, and being ready for the government’s staged plan — large companies filing returns electronically by 2027, and every business by 2028.
The incentives under Ministerial Regulation No. 389 ran to 31 December 2025, so check what is available now before counting tax relief in the business case.