Regimes

A regime is selected by the regimeModule key on the buyer jurisdiction's tax profile (from laravel-geo).

Shipped

• EuVatRegime (eu-vat) — destination VAT at the customer's Member State rate; intra-EU B2B supplies to a validated customer reverse-charge.
• NationalTaxRegime (uk-vat, ch-vat, no-vat, au-gst, nz-gst, mx-iva) — single national-rate VAT/GST with a cross-border B2B reverse charge.

Both share DestinationTaxRegime: a cross-border B2B supply to a tax-ID-validated customer reverse-charges; everything else is taxed at the place-of-supply rate.

Reverse charge

Reverse charge applies only when the supply is cross-border (the selling entity is not established in the buyer's country), the customer is a business, and their tax ID is validated (customerTaxIdValidated: true) — because zero-rating legally hinges on a valid customer VAT/registration number. Otherwise destination tax is charged.

Sub-federal regimes

• UsSalesTaxRegime (us-sales-tax) — destination sourcing with three gates: the state must be resolved (rooftop via an AddressGeocoder), the seller must have nexus in it (a registration), and the product must be taxable there (ProductTaxability). Otherwise it returns NotRegistered or Exempt — never a wrong charge. A jurisdiction with no resolved state raises JurisdictionNotResolved.
• CaGstRegime (ca-gst) — Canada has no local sales tax, so a province (subdivision) fully determines the combined GST/HST(/PST/QST) rate. A cross-border non-resident B2B supply to a registered customer is self-assessed (reverse charge).

A jurisdiction whose regimeModule is not registered at all still raises UnsupportedJurisdiction — never guessed.