Vietnam · VN
The Vietnamese mã số thuế
Vietnam has VAT — thuế giá trị gia tăng — and one number carries it: the mã số thuế, which is also the enterprise registration number. It is the number every Vietnamese invoice is issued against.
Format: VN + 10 digits, or 13 for a branch
Example: VN0100109106
Issued by: the Tổng cục Thuế, the General Department of Taxation.
The format
A mã số thuế is ten digits. Since the merger of tax and business registration, it is the same number as the enterprise registration number on the certificate — one identifier, not two, which spares Vietnam the Irish problem of a company register that cannot be reached by tax number.
A branch or dependent unit carries the parent's ten digits followed by three of its own, written with a hyphen: 0100109106-001. Thirteen digits is therefore a valid number and not a typo; it identifies the branch, and the register answers for it under that number.
The tenth digit is a check digit, but the algorithm is not published in a form that can be relied on, so Vatlas does not reject a Vietnamese number offline — a mistyped one has to be asked about.
What the register states
The tax administration publishes a status in words rather than as a code. NNT đang hoạt động — the taxpayer is operating — is the live one; the several ways of having stopped are written out too, from ngừng hoạt động to a closed tax code. Vatlas maps the live wording and the stopped wordings, and reports anything it has not seen before as unknown rather than guessing at it.
Finding the company behind the number
The official lookup, and why it cannot be automated
The Tổng cục Thuế publishes the taxpayer file at tracuunnt.gdt.gov.vn and the national business registration portal publishes the companies. Both are free, both are authoritative, and both put a captcha in front of every query. Neither publishes a downloadable file. There is, in short, no way for a program to ask the Vietnamese register anything.
What is reachable instead
The tax administration's data is republished openly by VietQR, keyed by tax code, as JSON and with no key. That is what Vatlas calls, and it says so: a Vietnamese answer names VietQR as its source, not the register. It is an aggregator, and treating it as the tax authority's own word would be a claim we are not in a position to make.
Expect a hit in about a second and a miss in eight to fourteen: the service goes upstream before it will tell you a number does not exist.
Vietnam-specific pitfalls
- Thirteen digits is normal. It is a branch, not a bad number. Keep the whole thing.
- No offline validation. The check digit cannot be verified reliably, so a typo costs one lookup.
- The source is an aggregator. Authoritative data, republished — and where that matters for evidence, it matters.
- A miss is slow. Budget for ten seconds or more on a number that does not exist.
- One number for two purposes. The tax code is the registration number; there is no second identifier to reconcile.
One API, one response shape
Vatlas turns a business tax number into a company record: legal name, national identifier, legal form, status and address. Vietnam — the same call and the same response as for every other country covered.
curl "https://api.vatlas.dev/v1/lookup/VN0100109106" \
-H "Authorization: Bearer $VATLAS_KEY"Response:
200 OK
{
"data": {
"vatNumber": "VN0100109106",
"countryCode": "VN",
"nationalNumber": "0100109106",
"nationalId": "0100109106",
"name": "TẬP ĐOÀN CÔNG NGHIỆP - VIỄN THÔNG QUÂN ĐỘI",
"legalForm": null,
"status": "active",
"address": {
"line1": "Số 5 phố Nguyễn Hữu An, Phường Cầu Giấy, TP Hà Nội",
"line2": null,
"postalCode": null,
"city": null,
"country": "VN"
}
},
"meta": {
"source": "VIETQR",
"sourceDate": "2026-09-15",
"sourceSince": "2026-09-15",
"sourceUpdatedAt": null
}
}meta.source names the register that answered (SIRENE, ARES, VIES…) and meta.sourceDate the day it said so: the publication date of the file for a register we import, the day of the call for one we query live. The shape of the response never changes from one country to the next.
Try it on your own numbers. An email address is all it takes to create an account, with 100 requests a month and a working key in about a minute.
Frequently asked
The mã số thuế in short
How many digits is a Vietnamese tax code?
Ten for a company, thirteen for one of its branches — the parent's ten plus a three-digit suffix.
Is the tax code the same as the business registration number?
Yes. Vietnam merged the two, so one number serves both.
Can I check a Vietnamese number on the tax authority's site?
By hand, yes. Not from a program: every query on the official portals is behind a captcha.
Where does the data come from, then?
From VietQR, which republishes the tax administration's data openly. We name it as the source rather than implying the register answered.
Does VIES cover Vietnam?
No. VIES answers for member states of the European Union only.
Business numbers in other countries
Last updated 15 September 2026.