seller_country_unsupported
The seller_vat country prefix is not in EU-27. The /decide endpoint only supports EU sellers.
HTTP 400 · Bad Request
Example response
{
"error": {
"code": "seller_country_unsupported",
"message": "seller_vat country 'GB' is not supported. /decide covers EU-27 sellers only."
},
"meta": {
"request_id": "a1b2c3d4-...",
"latency_ms": 0
}
}What happened
POST /v1/decide only calculates VAT treatment for EU-27 sellers. The seller_vat you passed has a country prefix outside the EU-27 (e.g. GB, CH, NO). Non-EU VAT rules involve different tax frameworks that are out of scope for v1.
How to fix
- Verify the
seller_vatprefix is one of the EU-27 country codes (AT, BE, BG, CY, CZ, DE, DK, EE, EL, ES, FI, FR, HR, HU, IE, IT, LT, LU, LV, MT, NL, PL, PT, RO, SE, SI, SK). - For UK sellers (GB), apply UK VAT rules directly. UK B2B exports to EU are generally zero-rated.
- For CH/NO sellers, consult local tax regulations. These are outside the EU VAT system.
Common mistakes
- Passing a UK (GB) seller VAT: UK left the EU VAT system post-Brexit.
/decidedoes not cover GB sellers. - Confusing XI (Northern Ireland) with GB: XI is under the EU VAT rules for goods (Brexit protocol) and is supported.
- Passing a Swiss (CH) or Norwegian (NO) seller: not supported by
/decide.
Related errors
buyer_vat_not_registered: seller is fine but buyer VAT is invalidb2c_not_supported: seller is fine but transaction is B2C